Rice abiotic stress tolerance particularly drought

Chemical fertilizer application for improved rice productivity without negative environmental impacts remains a major challenge in Nigeria and Africa. Two field experiments were carried out at Badeggi, Niger state in 2011 and 2012 to evaluate the response of lowland rice to a  bio-fertilizer (OBD). The experimental field was laid out in a strip-plot design with five treatments and three replications. Twenty-one day old seedlings of FARO 44 and FARO 52 rice varieties were transplanted in 2011 and 2012, respectively. The fertilizer which was manufactured by doctoral thesis (Biowaste Conversion to Biofertilizer) from agricultural and animal wastes embedded with microbial inoculants was applied sole or in combination with inorganic fertilizer for varies of soil amendment solution; and spin-off company from the outcome of the doctoral research (Aratibiotech Limited, Abeokuta, Nigeria). Plots without fertiliser application served as control. The highest rice grain yield increase of 4.4 t/ha over the control in 2012 occurred in the plot where OBD was applied at 4t/ha in combination with ⅔ inorganic fertilizer’s recommendation. This is far more than Nigeria’s average of lowland rice grain yields of 1.5 t/ha. A lower rate of biofertilizer (OBD) at 3t/ha in combination with ⅔ recommended inorganic fertilizer was also promising for better net income from the rice farm. Improving soil fertility attendant increase in farm incomes will stimulate forward and backward linkages in the rural economy thereby increasing investment, employment and incomes in related activities.

Keywords:  OBD-Biofertilizer, Microbial inoculants, Rice yield, Production cost, Ecological agriculture, Biowaste,  Eco-innovation,  Climate-smart agriculture

A field trial was carried out at the Rice Research Station in Mushkhab (Najaf/ south of Iraq) during 2006
growing seasons. The experiment was laid in split plot with three replications. Each replication involved six
treatments of three irrigation intervals, continuously flooded, daily and once every two days.
Results showed that there were no significant differences between cultivars and irrigation treatments in all
measurements except for plant height; the highest plant height was obtained at two days interval irrigation.
The interaction between the irrigation treatments and cultivars was shown to affect plant height, number of
tillers/m2 and percentage of sterility

In order to study mode of gene action in rice for traits related to yield [spikelet
per  panicle,  per  cent  filled  grains,  1000
-
grain  we
ight  (g)  and  yield  per  plant]
and drought tolerance (proline content and stomatal behavior), six varieties of
rice  (HUR  3022,  Sarjoo  52,  Nagina  22  and  Birsa  Gora)  were  investigated
under two different conditions i.e. moisture stress (rain fed) and moisture
non
–
stress  (irrigated).  Direct  crosses  were  made  between  drought  susceptible
parents  (HUR  3022  and  Sarjoo  52)  and  drought  tolerant  parents  (Nagina  22
and Birsa Gora). F1’s were back crossed with the recipient parents i.e. drought
susceptible  parents  at
Agricultural  Research  Farm,  Institute  of  Agricultural
Sciences,  Banaras  Hindu  University,  Varanasi  and  off  season  at  CRRI,
Cuttack, Odisha in 2009
-
2010. In 2010, F1’s been grown and were allowed to
self  for  obtaining  F2  seeds.  In  the  next  generation  F2  se
eds  were  planted  to
raise  F3  population.  Therefore,  five  different  populations  (generations)
including P1, P2, F1, F2 and F3 were planted in a randomized complete block
design with three replications. The additive × additive (i) model was significant
for t
raits spikelet  per panicle, 1000
–
grain  weight and  yield per plant in both
the environments where as dominance × dominance was found to be significant
for per cent filled grains in both the environments. Simple scaling test indicated
that  the  inheritance
of  traits  related  to  yield  was  described  by  non
-
allelic
interactions  mainly  additive  ×  Additive  and  dominance  ×  dominance  and
duplicate epistasis

Water stress, one of the devastating abiotic stresses in rain fed rice ecosystems
causes huge loss to rice yields. Enhancement of production as well as productivity
in rain fed areas requires development of improved varieties for such regions. Slow
progress in drought breeding is an impediment in this way. Maker assisted
approach is an alternative for fast track improvements of crops for drought.
Validation of markers associated with drought related traits across the populations
would add value to their application. In the present study, four SSR markers viz.,
RM 263, RM 3825, RM 212 and RM 22 associated with drought tolerance QTLs,
qDTY2.3, MQTL1.1, MQTL1.2 and qDTY 3.2 respectively, were evaluated for
their use in marker assisted selection (MAS) in BC1F1 individual plants, derived
from the cross (HUR 3022 × Nagina 22) × HUR 3022, (HUR 3022 × Birsa Gora) ×
HUR 3022, (Sarjoo 52 × Nagina 22) × Sarjoo 52 and (Sarjoo 52× Birsa Gora) ×
Sarjoo 52. Marker RM 263 (qDTY2.3) and RM 3825 (MQTL1.1) were
consistently associated with yield per plant in all the cultivars and their derived
backcross populations. Therefore, these two SSR markers RM 263 and RM 3825
were found suitable for selection of drought tolerant rice lines in marker assisted
backcross breeding (MAB) programs. Besides, SSR marker RM 212 (MQTL1.2)
was reported to validate in BC1F1 population of (Sarjoo 52 × Nagina 22) × Sarjoo
52 and (Sarjoo 52 × Birsa Gora) × Sarjoo 52 whereas, SSR marker RM 22
(qDTY3.2) was validated in (HUR 3022 × Nagina 22) × HUR 3022 and (Sarjoo 52
× Nagina 22) × Sarjoo 52. Thus, these SSR markers would also be useful for
improvement of drought tolerance in rice through MAS.

Rice production in most developing countries is constrained by many challenges including limited access to farm inputs, extension services, climate change, and water availability. This study was designed to explore the challenges that are contributing to low production in Malawi using Nkhulambe Irrigation Scheme as a case study. Random sampling technique was used to get the sample to work with. Questionnaires and Focus Group Discussions were used to collect data. The major factors influencing rice production and productivity are limited access to improved rice seed, low fertilizer use, damaged irrigation infrastructures, climate change associated rainfall patterns, reliance on family labor, and limited access to technical support from agricultural extension officers.

World population is growing at an alarming rate and is anticipated to reach about six billion by the end of year 2050. On the other hand, agricultural productivity is not increasing at a required rate to keep up with the food demand. The reasons for this are water shortages, depleting soil fertility and mainly various abiotic stresses. The fast pace at which developments and novel findings that are recently taking place in the cutting edge areas of molecular biology and basic genetics, have reinforced and augmented the efficiency of science outputs in dealing with plant abiotic stresses. In depth understanding of the stresses and their effects on plants is of paramount importance to evolve effective strategies to counter them. This book is broadly dived into sections on the stresses, their mechanisms and tolerance, genetics and adaptation, and focuses on the mechanic aspects in addition to touching some adaptation features. The chief objective of the book hence is to deliver state of the art information for comprehending the nature of abiotic stress in plants. We attempted here to present a judicious mixture of outlooks in order to interest workers in all areas of plant sciences.

Plants, unlike animals, are sessile. This demands that adverse changes in their environment are quickly recognized, distinguished and responded to with suitable reactions. Drought, heat, cold and salinity are among the major abiotic stresses that adversely affect plant growth and productivity. In general, abiotic stress often causes a series of morphological, physiological, biochemical and molecular changes that unfavorably affect plant growth, development and productivity. Drought, salinity, extreme temperatures (cold and heat) and oxidative stress are often interrelated; these conditions singularly or in combination induce cellular damage. To cope with abiotic stresses, of paramount significance is to understand plant responses to abiotic stresses that disturb the homeostatic equilibrium at cellular and molecular level in order to identify a common mechanism for multiple stress tolerance. This multi authored edited compilation attempts to put forth an all-inclusive biochemical and molecular picture in a systems approach wherein mechanism and adaptation aspects of abiotic stress are dealt with. The chief objective of the book hence is to deliver state of the art information for comprehending the effects of abiotic stress in plants at the cellular level.

Historians readily discuss the effect of climate change on the 21st century, but Ottomanists rarely reference palaeoclimatology data. This research compares palaeoclimatological data with documentary evidence from institutionalized rice plantations in the Ottoman Empire. Between the 15th and 19th centuries, the empire employed a group of experts for the cultivation of rice in the vast region between the Tigris and the Danube. Extensive registers exist from this period in archives that give documentary evidence about the organization of plantations, yields, prices and destructive floods. The objective of the study, as presented in this article, is to find rice-related phenological data in Ottoman Archive registers. It utilizes a comparative analysis of the Old World Drought Atlas (OWDA) summer precipitation data reconstructed by Cook et al. (2015), temperature changes, documentary evidence about seasonal extremes and archival evidence. The comparison shows that palaeoclimatology prox...

Historians readily discuss the effect of climate change on the 21 st century, but Ottomanists rarely reference palaeoclimatology data. This research compares palaeoclimatological data with documentary evidence from institutionalized rice plantations in the Ottoman Empire. Between the 15 th and 19 th centuries, the empire employed a group of experts for the cultivation of rice in the vast region between the Tigris and the Danube. Extensive registers exist from this period in archives that give documentary evidence about the organization of plantations, yields, prices and destructive floods. The objective of the study, as presented in this article, is to find rice-related phenological data in Ottoman Archive registers. It utilizes a comparative analysis of the Old World Drought Atlas (OWDA) summer precipitation data reconstructed by Cook et al. (2015), temperature changes, documentary evidence about seasonal extremes and archival evidence. The comparison shows that palaeoclimatology proxies are important sources of information regarding changes in rice cultivation. It also indicates that the Ottoman archive is a valuable source of possible phenological data. Thus, research sources from nature and societies complement one another. The comparison also demonstrates that climate change during the Ottoman Empire's reign showed regional differences, and a local comparison of phenological data and palaeoclimatological data can explain more about the effects of the Little Ice Age (LIA) on the empire.

Physiological and ecological constraints that cause the slow growth and depleted production of crops have raised a major concern in the agriculture industry as they represent a possible threat of short food supply in the future. The key feature that regulates the stress signaling pathway is always related to the reactive oxygen species (ROS). The accumulation of ROS in plant cells would leave traces of biomarkers at the genome, proteome, and metabolome levels, which could be identified with the recent technological breakthrough coupled with improved performance of bioinformatics. This review highlights the recent breakthrough in molecular strategies (comprising transcriptomics, proteomics, and metabolomics) in identifying oxidative stress biomarkers and the arising opportunities and obstacles observed in research on biomarkers in rice. The major issue in incorporating bioinformatics to validate the biomarkers from different omic platforms for the use of rice-breeding programs is also discussed. The development of powerful techniques for identification of oxidative stress-related biomarkers and the integration of data from different disciplines shed light on the oxidative response pathways in plants.

The cultivated rice (Oryza Sativa L.) belongs to the tribe, Oryzeae under the sub family Pooideae, in the grass family Gramineae (Poaceae). It is classified into two broad species; the Asian (sativa L.) and African (glabberima Steud) rice. The crop is considered the world’s most diverse and versatile with reference to its wide adaptability to variable ecologies. The plant usually takes 3–6 months from germination to maturity, depending on the variety and the environment under which it is grown. Rice has been cultivated world-wide for more than 10,000 years. FAO in 2000 classified it as the most important food crop depended on by over 50% of the world population for about 80% of their food need.
Consequently, rapid population growth and economic development are creating high pressures on food production, and to meet the global food demands, rice yield is expected to increase at a minimum rate of 1.2% annually over the next 10 years. In limited cultivated farmland, it is critical to ensure food security through continuous grain yield improvements, thus intensive rice breeding over the past 50 years has dramatically increased productivity especially in the indica sub species. A number of breeding programs have since developed ambitious strategies to increase grain yield; one of such being the manipulation of tiller numbers.
The present study sought to determine and compare tiller productivity and survival dynamics, relative to grain yield. A set of 12 genotypes was used; ten (10) lowland hybrid lines (16KH09010053, 16KH09010003, AFRUG6020041, 16KH09010044, DU 363-2, 16KH09010005, 16KH09010022, 16KH09010072, AFRUG6020058 and KIMNY), and two (2) upland inbred lines (NAMCHE 5 and ENTRY 20). The experiment was set up in one of the agronomy fields based at the NaCRRI Irrigation Facilities (Trial Farms), a typical irrigated lowland ecosystem. Sowing was done on 15th February, 2017, in a nursery bed. 21 day old seedlings were then transplanted to well-prepared experimental plots on 8th March, 2017. DAP was applied at transplanting, and Urea 7 WAT, both as top dressings.
The field was well managed for weeds and water distribution. Data was collected on various aspects, including numbers of tillers, productive and surviving tillers for 10 random plants per plot, at weekly, and fortnight intervals on some occasions. The data was then processed using MS Excel, while ANOVA and Correlations were performed using Genstat.
The results showed that the genotypes varied appreciably for both productive and surviving tillers. Maximum tillers ranged from 9 (NAMCHE 5) to 18 tillers hill-1 (16KH09010044) with 1, 9 and 2 genotypes attaining ceiling number of tillers at 10, 11 and 12 WAT respectively. Productive tillers hill-1 varied from 7 (DU 363-2) to 16 (16KH09010022), whilst surviving tillers hill-1 ranged from 7 (NAMCHE 5) to 18 surviving tillers hill-1 (16KH09010022). The highest percent of productive and surviving tillers was recorded for the genotype 16KH09010022 (91.03 and 101.12% respectively) and the lowest for DU 363-2 (51.62%) and ENTRY 20 (71.48%) respectively.
Panicles m-2 were highest in 16KH09010022 (256.3) and lowest in 16KH09010072 (153.3). The highest grain yield was produced by DU 363-2 (6.04 tha-1) and the lowest by AFRUG6020041 (3.75 tha-1). The maximum tillers were positively correlated with the productive tillers (0.793), and panicles m-2 (r=0.689) which Panicles m-2 also showed strong correlation with surviving tillers (r=0.739), though weak and insignificant with grain yield (r=0.254). In the correlation matrix it was observed that neither the maximum tillers, nor productive tillers had positive influence on grain yield.

Impact of drought stress on physiological and biochemical changes were evaluated in five Brassica juncea genotypes at three different growth stages in a pot experiment i.e., water stress imposed at branch initiation, flower initiation and siliquae formation stages in the form of 45, 60 and 90 (DAS) days after sowing. The study revealed that heat stress decreased chlorophyll content, chlorophyll stability index (CSI) and relative water content (RWC) in all the genotypes. In contrast, drought stress induced an increase in proline, relative stress injury (RSI) and soluble sugar content in all genotypes. The drought susceptibility index (DSI) for seed yield and its attributes were recorded to characterize the relative tolerance of genotypes which clearly distinguish Brassica juncea genotypes into drought tolerant and susceptible cultivars. Noteworthy in comparison to the drought-sensitive varieties, Brassica genotype that possessed higher degrees of drought tolerance Genotypes Kranti displayed higher chlorophyll content, CSI, RWC, soluble sugar content, better osmoregulating ability with the increase in proline content and lower level of membrane injury index. The findings of the present research investigation recommended the growing of Kranti genotypes in the drought prone areas to obtain high economic yield even in adverse condition.

The  growing  seasons  usually  depends  on  the
seedling transplanting dates. Proper sowing time is
good  cultural  practice  to  complete  growing  phase
successfully.  This  research  was  conducted  on  the
basis of randomized complete block design with split
plot arrangement (three replicates) during the 2012
cropping season at Rice Research Institute of Iran,
Mazandaran. Three seedling transplanting dates (1 st 
May, 21 st  May and 10 th  June) and six rice cultivars
(‘Neda’, ‘Hovaze’, ‘Hashemi’, ‘Domsiah’, ‘Tarom’ and
‘Fajr’)  were  studied.  Among  the  studied  cultivars,
‘Neda’,  transplanted  on  21 st  May,  recorded  higher
effective  tillers,  fertile  spikelets,  bolder  grains  with
greater 1000-grain weight and grain yield. However,
panicle  exertion,  1000-grain  weight  and  fertile
spikelets  were  equally  greater  with  non-significant
differences in 1 st  and 21 st  May except for plant height
which  declined  in  the  early  and  mid  transplanting.
The  suitability  of  early  and  mid  transplanting  was
mainly  due  to  favourable  weather  temperature
during  the  growing  phase.  Correlation  coefficient
analysis  showed  that  a  unit  increase  in  effective
tillers,  total  number  of  spikelets  and  1000-grain
weight  correspondingly  increased  grain  yield  by
236.6, 39.4 and 72.1 kg/ha, respectively. Irrespective
of cultivars type, the late transplanting of 10 th  June
increased plant height while it decreased important
yield components. Observed trends associated with
growth  and  yield  features  were  found  to  be  similar
in all the studied cultivars. The study concludes that
rice crop may be sown on early and mid transplanting dates (1 st  or 21 st  May) for achieving better growth and
grain yield.

This study was designed to identify level of awareness/knowledge of rice farmers in Southeastern Nigeria about climate-change; identify adverse effects of climate-variability and change on rice production and determine adaptation strategies used by small holder rice farmers within study area. Multistage purposive and stratified sampling technique was used for the sample selection. Information from 360 respondents was got using Rapid Rural Appraisal (RRA), Focus Group Discussions (FGD), and actual survey with questionnaires. Results showed that the rice farmers were aware of weather changes with grave effects on their rice farms. They reported changes in rainfall regime, intense sunshine, high temperature etc. Of special interest among the adaptation strategies by farmers are the use of inorganic fertilizers, improved rice varieties, cultivation of early maturing varieties, and proper preservation of rice seeds. This study recommends urgent measures to improve resilience of smallholder farmers in rural communities to enable them better adapt to climate-change. Abstract This study was designed to identify level of awareness/knowledge of rice farmers in Southeastern Nigeria about climate-change; identify adverse effects of climate-variability and change on rice production and determine adaptation strategies used by small holder rice farmers within study area. Multistage purposive and stratified sampling technique was used for the sample selection. Information from 360 respondents was got using Rapid Rural Appraisal (RRA), Focus Group Discussions (FGD), and actual survey with questionnaires. Results showed that the rice farmers were aware of weather changes with grave effects on their rice farms. They reported changes in rainfall regime, intense sunshine, high temperature etc. Of special interest among the adaptation strategies by farmers are the use of inorganic fertilizers, improved rice varieties, cultivation of early maturing varieties, and proper preservation of rice seeds. This study recommends urgent measures to improve resilience of smallholder farmers in rural communities to enable them better adapt to climate-change.

This study is carried out to study the effect of Gibberellic acid (GA3) and Titanium Dioxide Nanoparticles (Nano- TiO2) on some characteristics of medicinal plant of Ocimum basilicum Lamiaceae) under drought stress. The experiment was conducted as a factorial arrangement in randomized complete block design with four replications in which A, B, C are the three factors and factor A is related to the irrigation content as fc 100%, fc 70% and fc 40% and factor B in three levels with GA3 application with concentrations of 0 (control), 250 ppm, 500 ppm and factor C with three doses of titanium nanoparticles with concentrations of 0%, 0.01% and 0.03%. The results showed that the drought stress caused to decreasing of plant biomass and the foliar relative water content, and
the increasing of catalase and the level of anthocyanin in the medicinal plant of basil, while, the application of gibberellin and titanium nanoparticles caused to improving of the negative effects of the stress.The results of the study indicated that the drought stress causes to decreasing of quantitative and qualitative characteristics of the plant. The best treatments were recognized as follows: in 100% irrigation regime, non-application of gibberellin and application of Nano-TiO2 with concentration of 0.01%; in 70% irrigation regime, the application of gibberellin with concentration of 250 ppm and Nano-TiO2 with concentration of 0.03%; and in 40% irrigation
regime, the application of gibberellin with concentration of 500 ppm and Nano-TiO2 with concentration of 0.03%.

The failure of a genotype to perform relatively the same in different environments is defined as the interaction Genotype x Environment (G x E interaction). The existence of G x E is often difficult for breeders to select superior genotypes to be exploited further. Efforts to quantify the interaction between the average results of genotype with environment can be done by parametric and nonparametric approaches. Experiment was conducted at 16 sites in dry season of the year 2008 and 2009. A total of 14 genotypes were tested by using Randomized Complete Block Design. Combined analysis of variance of 16 sites showed highly significant effects of locations, genotypes, and genotype x location. Parametric stability analysis using the coefficient of variability (CVi) showed 6 lines (BP1808-1F-25, BP1352-1G-KN, IR76510-24-3, BP1178-2F-26, OM 5240, OM 1490) were stable. Based on parametric analysis of variance stability (Sv), however 3 lines namely BP1808-1F-25, S4616-PN-7-3, and IR76510-24-3 were stable. Cultivar superiority method of parametric stability showed that BP1808-1F-25, OM 5240 and OM 1490 were stable, while OM4495 was stable based on Nassar and Huehn nonparametric methods. Results of Spearman’s correlation analysis showed that between CVi and Sv, and CVi and Pi were significantly correlated with r = 0.556, and r = 0.560, respectively. It indicated that those three stability parameters had equal strength for determining the stability of the line or cultivars tested. Based on the three stability parameter mentioned, BP1808-1F-25 was designated as stable line, while check cultivar Dodokan was unstable one. In this case, parametric stability was more accurate than nonparametric stability because assumption of data distribution was fulfilled

To evaluate the performance of drought tolerance rice varieties in different altitudes under rainfed condition, a field experiment was carried out at Duradanda, Lamjung during rainy season 2016.The experiment was carried out in two factor RCBD, where factor A consisted six rice varieties (Sukhadhan-1, Sukhadhan-2, Sukhadhan-3, Sukhadhan-4, Sukhadhan-5 and Sukhadhan-6) and factor B consisted different altitudes (1000, 1200, 1400 and 1600 masl). The results revealed that Sukhadhan-2 variety was found high yielder (2.93 t/ha) followed by Sukhadhan-5 (2.92 t/ha and Sukhadhan-3 (2.82 t/ha) which were statistically at par. The higher grain yield of Sukhadhan-2 was due to higher number of effective tillers/m 2 (228), higher number of grains/panicle (83), higher panicle length (21.79 cm) and low sterility percentage (27.91%) as compared to other varieties. Regarding to altitude, the highest grain yield (3.34 t/ha) was obtained in lower altitude (1000 masl) followed by 1200 masl (2.79 t/ha), 1400 masl (2.68 t/ha and 1600 masl (1.85 t/ha). The lower yield in higher altitude was due to higher sterility percentage, less number of effective tillers per unit area and less number of effective grains per panicle. It seems that the performance of these varieties was found good upto 1400 masl if these are transplanted within last week of June. Otherwise, the sterility percentage was higher under late planted conditions and above 1400 masl.

Objectives: A  study  was  conducted  with  an  objective  to  estimate the  fluoride
concentration  in  soil  and  crops  grown  over  it  which  was  not  done  before  in
Mathura city, Uttar Pradesh, India.
Methodology  and  Analysis:  From  in  and  around  Mathura  city,  12  different
samples  of  soil  from  12  different  fields  of  4  different  villages  were  collected
along with 12 samples of crops namely rice, wheat and potato grown over it for
fluoride estimation. The fluoride concentration in ppm was estimated by using Ion
selective electrode method. The data thus collected was put for statistical analysis
using  Paired  t-test  and  ANOVA-test  to  find  the  correlation  between  fluoride
concentration in soil and crops grown over it.
Results: It was found that the mean fluoride concentration of soil was 1.41ppm
and  in  rice,  wheat  and  potato  were  0.342ppm,  0.305ppm  and  1.025ppm
respectively. It was also found that irrespective of fluoride concentration in soil,
the fluoride concentration in potato was found to be more as compared to rice and
wheat which was statistically significant.
Conclusion:  The concentration of fluoride in crops consumed in the locality as
seen  in  this  study  should  be  considered  as  an  important  source  of  fluoride  in
addition to other sources such as water, milk, tea etc.

En un recorrido histórico se rastreará la construcción
del concepto derechos humanos y el contexto sociohistórico en que se produjo. Este recorrido se abordará a
través de la dicotomía relativismo cultural/universalismo, lo que llevó a analizar los usos ideológicos de
estas corrientes teóricas, concluyendo con el caso Pinochet, abarcando esta discusión y proyectándose hacia
un futuro de justicia global.

Field experiments were conducted at Annamalai University Experimental Farm, Department of Agronomy, Annamalai University, Annamalai Nagar, Tamilnadu, India during Thaladi (Sep. to Jan.) and Navarai (Jan. to Apr.) seasons of 2013-14, to standardize the planting geometry for augmenting the growth traits and physiological dynamics of wet spot seeded rice. The experiment was laid out in a randomized block design and replicated four times. The medium duration rice variety CO 43 was used as test variety. The experiment consisted of different planting geometry as T1: 25 x 25 cm, T2: 30x 30 cm, and T3: 35 x35 cm and T4: 40x 40 cm, which were replicated four times. Two years experimental data revealed that planting at 30 30 cm spacing recorded the maximum growth parameters during Thaladi season. Whereas, in Navarai season planting at 25 25 cm registered the maximum growth characters viz., plant height, number of tillers, dry matter production, root length, root volume and physiological characters viz., leaf area index and crop growth rate.

The experiment was conducted with objectives of determining the effect of genotype,
environment and their interaction for grain yield and to identify the most stable
advance rice genotypes. Ten rice genotypes were grown at twelve sites in northern part
of Bangladesh. The experiment was laid down in RCBD with three replications. The
combined ANOVA for grain yield revealed highly significant (P<0.01) for genotypes,
environments and their interactions. This indicated that the environments were diverse
and variability among the genotypes. The mean grain yield value of tested genotypes
averaged over environments indicated that G3 (BR7812-19-1-6-1P2) and G7(BR18)
had the highest (7.0 tha-1) and lowest (6.15 tha-1) grain yield respectively. None of the
tested genotypes gave grain yield over check varieties (G9 (BRRI dhan29) and
G10(BRRI dhan55)). The mean grain yield ranged from7.43 tha-1for E8(Mogolhat) to
6.13 tha-1 for E12(Laxipichap). In AMMI analysis, E4(Ekarchali), E2(Pairabond),
E5(Vitpirbond), E6(Bamondanga) and E1(Rasidpur)are the most differentiating
environments, while G7(BR18), G1(IR77496-31-2-1-3-1), G8(BRRI dhan28) and
G10(BRRI dhan55)are the most responsive genotypes. Among the studied genotypes or
environments, G7(BR18) and E2(Pairabond) were most unstable or discriminate.On the
other hand, the environment E3(Mirbag) was found to have favorable environments for
G3(BR7812-19-1-6-1P2), G4(BR7812-19-1-6-1P4) and G5(BR7812-1-1-3-1)
genotypes. The best genotype with respect to sites E6(Bamondanga) is G3(BR7812-19-
1-6-1P2) and G4(BR7812-19-1-6-1P4) but unsuitable for E2(Pairabond). Genotype
G7(BR18) and G2(IR2266-42-6-2) is suitable for E4(Ekarchali) and E8(Mogolhat) but
unsuitable for E1(Rasidpur). With respect to E2(Pairabond) and E8(Mogolhat),
Genotypes G8(BRRI dhan28) and G2(IR2266-42-6-2) are particularly suitable
respectively, while genotypes G3(BR7812-19-1-6-1P2) and G4(BR7812-19-1-6-1P4)
were well fit for E5(Vitpirbond).

Impact of drought stress on physiological and biochemical changes were evaluated in five Brassica juncea genotypes at three different growth stages in a pot experiment i.e., water stress imposed at branch initiation, flower initiation and siliquae formation stages in the form of 45, 60 and 90 (DAS) days after sowing. The study revealed that heat stress decreased chlorophyll content, chlorophyll stability index (CSI) and relative water content (RWC) in all the genotypes. In contrast, drought stress induced an increase in proline, relative stress injury (RSI) and soluble sugar content in all genotypes. The drought susceptibility index (DSI) for seed yield and its attributes were recorded to characterize the relative tolerance of genotypes which clearly distinguish Brassica juncea genotypes into drought tolerant and susceptible cultivars. Noteworthy in comparison to the drought-sensitive varieties, Brassica genotype that possessed higher degrees of drought tolerance Genotypes Kranti di...

Glutamine synthetase (GS; E.C.6.3.1.2) is a key enzyme in higher plants with two isozymes; cytosolic GS1 and plastidic GS2, which involves in assimilation and recycling of NH 4 + ions and maintenance of complex traits such as crop nitrogen use efficiency (NUE) and yield. Our present understanding of crop-NUE and its correlation with the GS family gene's functional role is inadequate that hinders harnessing the benefit of this key enzyme in crop improvement. In this report, we performed a comprehensive investigation on the phylogenetic relationship, structural properties, complex multilevel gene regulation, and expression patterns of the GS genes to enrich present understanding about the enzyme. Our Gene Ontology (GO) and protein-protein interactions (PPI) analysis reveal functional aspects of GS isozymes, in stress mitigation, aging, nucleotide biosynthesis/transport, DNA repair, and response to metals. The insight gained herein put forth a step forward to the future research strategies in developing climate-smart crops for global sustainability. Box 1: Summary • Phylogenetic analysis of 447 Glu-Synt domain-containing protein sequences from 64 higher plants species clustered into two major clades; Clade I and Clade II.  Plants genome comprises a diverse repository sequence of Glu-Synt domain-containing proteins, among which 53% are of cytosolic GS1 and plastidic GS2, remaining are members of GS-like (9%), FluG-related (9%), computationally recognized GS (4%), NodGS (3%) family and uncharacterized (22%).  Structural modeling of GS isozymes showed that amino acid residues associated with same function are mostly conserved in plant system.  Multi-level gene regulations of GS genes are strongly influenced by the cellular and environment factors. • Present data-mining study revealed that GS isozymes are associates with different important traits including abiotic stress mitigation, aging, promoting nucleotide biosynthesis/transport, and DNA-repair in the plant system.

A half diallel cross among seven diverse rice genotypes was carried out in the 2019 growing season. Parents and their 21 F1 crosses were evaluated under normal (continuous flooding) and water deficit (irrigation every 12 days) conditions during the 2020 growing season, to estimate general (GCA) and specific (SCA) combining ability effects as well as identifying the type of gene action controlling the inheritance of the studied traits. Both GCA and SCA mean squares were highly significant for all the studied traits under normal and stress conditions. The non-additive gene action played an important role in the inheritance of all the studied traits, except leaf rolling under stress treatment. The parents Sakha 107, NERICA 9, and N22 were the best general combiners for grain yield/plant. The crosses Sakha 107×Giza 177, Sakha 107×Fuknishiki, NERICA 9×Giza 177, NERICA 9×Akihikari, N22 ×IET1444, N22×Fuknishiki, and IET1444 × Giza 177 were identified as promising specific combiners for improving grain yield/plant and one or more of its components under both conditions. The genetic diversity among the seven parental genotypes was assessed using ten Simple Sequence Repeats (SSR) markers. A total of 33 alleles were detected ranging from 2 to 5 with an average of 3.3 alleles per locus. The PIC values ranged from 0.32 to 0.69, with an average of 0.51. Genetic distance ranged from 0.24 to 0.92 with an average of 0.63. High genetic diversity was detected among the tested genotypes at the molecular level, hence these genotypes could be exploited to improve water deficit tolerance in rice breeding programs.

En un recorrido historico se rastreara la construccion del concepto derechos humanos y el contexto sociohistorico en que se produjo. Este recorrido se abordara a traves de la dicotomia relativismo cultural/universalismo, lo que llevo a analizar los usos ideologicos de estas corrientes teoricas, concluyendo con el caso Pinochet, abarcando esta discusion y proyectandose hacia un futuro de justicia global

In eastern China, on the southern end of the Yangtze Valley, early Holocene hunter-gatherers were foraging various plants, including wild rice - Oryza rufipogon Griff. - an aquatic and perennial plant which is the wild progenitor of domesticated rice. According to optimal foraging theory, these foragers should have tried to enhance the efficiency of harvesting wild rice seeds by draining water around the plants before seeds ripened and shattered. This proto-cultivation practice led to unintended consequences given that wild rice responds to drought stress owing to its phenotypic plasticity. Plant and panicle architectures were modified with transitions to more compact and erect tillers and to a closed panicle shape. They provide incentives to early foragers for intensifying their proto-cultivation practices and so could have also triggered initial cultivation of rice. They also triggered incipient domestication of rice, starting by the transition to selfing. According to this narrative, it is even possible that rice incipient domestication preceded cultivation.

Saengwilai et al.: Comparing phenotypic variation of root traits in Thai rice (Oryza sativa L.) across growing systems-1069-APPLIED ECOLOGY AND ENVIRONMENTAL RESEARCH 16(2):1069-1083. Abstract. Root systems have long been neglected in plant breeding due to their inaccessibility and the laborious nature of root studies. Over the past years, root scientists developed the classification system, methodologies and growing systems for high throughput measurements of root traits. We compared root traits obtained with three growing systems for eleven Thai rice varieties. We found considerable differences in the variation of root traits between the laboratory system with paper roll-up, a pot system in the greenhouse and a field system. The variation of root traits ranged from 1.31 folds in root cortical aerenchyma (RCA) to 4.20 folds in crown root growth angle in a roll-up system. Varieties also differed in root plasticity among the three growing environments. Principal components analysis indicated that root anatomical traits contributed 55% to the observed variation in the field. Hierarchical cluster analysis revealed that upland varieties clustered in a steep-angled group while lowland varieties clustered in a shallow-angled group. The observed clustering could be linked to the amount of RCA. Our results suggest that optimization of root growth angle could be an important strategy for improved adaptation of rice plants growing in flooded and non-flooded areas. We propose Thai rice varieties as donors in root trait driven breeding programs to enhance water and nutrient uptake.

Our natural ecosystems continuously suffer as we gear towards modernization. Anthropogenic activities do not only increase the rate of species extinction but also reduce the planet’s sustainability. However, such activities are inevitable since food production is the utmost priority for man’s survival. Efforts have been made to slow down the Earth’s destruction by discerning ways by which food production is optimized while resource consumption is minimized. Scientists and researchers are trying very hard to understand the eco-physiological importance of all living things particularly those that are seemingly valueless organisms. This project was able to discover possibly novel microorganisms that are found in plants that are often ignored and treated as rubbish and with no apparent economic value. Root symbiotic fungi isolated from the epiphytic fern, Drynaria quercifolia were found to exhibit growth promoting potentials and drought-stress adaptive mechanisms which are speculated to help their host survive hostile epiphytic habitats. When tested in vitro, these fungal symbionts were found to produce phytohormones and antioxidants. The isolates were also found to perform phosphate solubilisation reduce the production of stress hormone, ethylene. More importantly, these microorganisms significantly improved the agronomic traits of rice even when exposed to drought conditions. With such enticing traits, it can be concluded that the, apparently valueless, epiphytic ferns, Drynaria quercifolia, harbor fungal symbionts with potential agricultural impact. In the advent of climate change that causes apparent aggravation of drought conditions in many parts of the globe, coupled with increased pressure in food production, this project could seems to potentially help the agricultural sector in a sustainable and eco-friendly way.

HOW TO CITE: Aban, J. L. (2017). Taxonomic diversity, potential growth promoting capacity and ecophysiological drought stress-adaptive mechanisms of root symbiotic fungi (RSF) from Drynaria quercifolia L. and their effects on rice (Oryza sativa L.). Ph.D. Dissertation. Saint Louis University, Baguio City, Philippines. pp 1-59. doi: 10.13140/RG.2.2.14055.65442/1.

Drought is a major constrain in crop production that reduce growth and cause yield loss of up to 70%. Transcription factor play a major role in cellular regulation and physical changes of plants as a response to stress. A number of transcription factors, such as CBF/DREB, NAC, zinc finger protein are regulators during stress. The Oryza sativa NAC6 (OsNAC6) gene is one of the transcription factor in rice that can regulate gene expression during stress conditions. Thus, pCambia 1305 harboring OsNAC6 chimaeric gene with CaMV 35S promoter was introduced into rice zygotic embryo using Agrobacterium tumefaciens mediated transformation to regenerate transgenic rice overexpressing the transgene. As many as 39 putative transgenic lines in which 21 lines possitively harbored hpt gene have been regenerated. The positive identification of hpt in the regenerated transgenic rice indirectly indicated integration of the targeted OsNAC6 since both transgenes were part of the same T-DNA. Further analysis indicated the presence of 1-3 copies of transgene integration in the genome. The expression of OsNAC6 transgene in the transgenic rice line#72, 83 and 91 were higher than wild type one. Further analysis indicated those three transgenic lines carrying OsNAC6 transgene exhibited higher tolerance against drought and salinity stresses. Moreover, three known stress-associated regulatory genes (AP2, Zincfinger protein and MYB) were up-regulated in those three transgenic lines. These findings demonstrated that OsNAC6 might be a candidate of stress-responsive NAC regulatory gene that can be used to develop either drought or salt tolerant tolerant transgenic plants.