Background: Cryopreservation opens new avenues in the field of genetic resource conservation, esp... more Background: Cryopreservation opens new avenues in the field of genetic resource conservation, especially in recalcitrant seeded palms such as arecanut for which field genebanks are exposed to pest and disease attacks and natural calamities. It is only through cryopreservation that the safety of the conserved germplasm can be assured at a relatively low cost for extended periods. Objective: The objective of this work was to standardize various aspects of arecanut pollen cryopreservation, viz. collection and desiccation of pollen, in vitro germination, viability and fecundity studies. Materials and methods: Pollens of three arecanut genotypes (Sumangala, Hirehalli Dwarf and Hirehalli Dwarf x Sumangala) were collected in December 2013-February 2014. In vitro viability tests were conducted using fresh and desiccated pollen. Desiccated pollen was cryopreserved by direct immersion in liquid nitrogen and cryostored for different durations (24 hours to 2 years). Viability and fertility studies were conducted using cryopreserved pollen. Results: Pollen extraction was achieved from fully opened male flowers by desiccation at room temperature (33-34 degree C). A medium containing 2.5 g/L sucrose was found to be best for in vitro germination at room temperature. There was no significant difference in germination between desiccated and cryopreserved pollen whereas pollen tube length decreased significantly after cryopreservation. Fertility studies using HD x Sumangala pollen cryostored for various durations (1 month, 1 year and 2 years) showed the setting of 70, 43 and 62%, respectively. Normal nut set was observed using cryopreserved pollen. Conclusion: Pollen cryopreservation is a viable option for germplasm conservation and hybridization programmes in arecanut.
Random Amplified Polymorphic DNA (RAPD) is a simple technique used for genetic analysis in many c... more Random Amplified Polymorphic DNA (RAPD) is a simple technique used for genetic analysis in many crops. The effectiveness of 45 RAPD primers were evaluated based on polymorphism information content (PIC) and marker index (MI) for their use in coconut. Among the RAPD primers, maker index ranged from 6.280 to 0.031. The primer OPBE 06 had the higher MI and accordingly other primers were ranked. Five, 10 and 15 primers were identified as informative primers. The dendrograms were constructed separately for informative primers and 45 primers using software NTSYS pc. The dendrogram obtained using 15 informative primers was comparable to that of 45 primers.
Coconut zygotic embryo culture has practical value in collection and exchange of germplasm overse... more Coconut zygotic embryo culture has practical value in collection and exchange of germplasm overseas and is done on different media protocols. Differences in plantlet survival and media composition led to a study with an objective to compare growth, leaf gas exchange characteristics and biochemical constituents of plantlets of dwarf and tall cultivars of coconut grown on four media viz., PCA-ARC, UPLB, IRD and CPCRI. A total of 960 embryos from two dwarf (COD and MYD) and two tall (WCT and LCT) cultivars of coconut were inoculated on four different media. The dwarfs germinated earlier than the talls. Maximum vitrification was observed in liquid media, viz. PCA-ARC followed by UPLB and IRD. At the time of transplantation to pots for acclimatization, plantlet morphological growth did not vary significantly. However, biochemical composition (reducing sugars, starch, total carbohydrates, free amino acids and proteins; the chl. a, b, total chlorophyll and chl. ‘a/b ratio’) of seedling leaves varied with cultivar and influenced by medium composition. Development of photosynthetic system was influenced by the composition of medium and readily usable carbon source in media seems to inhibit Pn. In general, plantlets raised on PCA-ARC and CPCRI media had higher in vitro and ex vitro survival rates followed by those raised on UPLB medium. Plantlets from IRD medium had lowest survival capacity. LCT and MYD plantlets survived better when grown on PCA-ARC medium, and WCT and COD plantlets survived better when raised on CPCRI medium. It is suggested that providing solid germinating medium to reduce vitrification loss; addition of auxins and reduction of salt concentrations in growth medium, reduction of sucrose concentration in rooting medium and gradual increase in PAR during rooting may help in early establishment of photosynthetic mechanism and better growth to increase the in vitro and ex vitro survival rates of coconut seedlings.
Vivipary is a problem in some dwarf varieties of coconut as their seed nuts show low germination ... more Vivipary is a problem in some dwarf varieties of coconut as their seed nuts show low germination compared to Talls. An experiment was carried out to study the extent of vivipary in dwarf coconut varieties (MGD, MYD, MOD and CGD) with WCT as control. Observations on nut traits like shape, colour, length, weight and water content of the seed nut, thickness, weight and polyphenol content of the husk, length and weight of embryo, TSS of nut water were recorded from 10-, 11- and 12-month-old nuts of each variety. Observations were also recorded at bimonthly intervals during November 2011-September 2012. None of the ten-month-old seed nut exhibited vivipary. However, few 11th old MOD nuts (3%) harvested during November showed vivipary. The results showed that the extent of vivipary was highest during September and least during January. Among the varieties, MYD exhibited maximum vivipary (24%) followed by MOD and MGD (16%) and the least was in WCT (0.6%). Vivipary was negatively correlated with various nut characters, husk thickness and weight. However, prevailing climatic conditions like amount of rainfall, number of rainy days and relative humidity during the preceding 30-day of harvest had significant positive correlation with vivipary. It is suggested that vivipary in dwarf varieties can be avoided by harvesting the seed nuts at the proper stage.
International journal of Bio-resource and Stress Management, Sep 30, 2022
The study was carried out at the Biotechnology Laboratory, Division of Crop Improvement, ICAR- Ce... more The study was carried out at the Biotechnology Laboratory, Division of Crop Improvement, ICAR- Central Plantation Crops Research Institute, Kasaragod during 2019−2021 to investigate the effect of electric current induction in coconut plumular callus obtained from WCT variety of coconut. Callus induction was observed when the plumules extracted from the embryo were inoculated into Eeuwens Y3 media supplemented with 16.5 mg l-1 2,4-D and 1 g l-1 activated charcoal. An electrical induction set up was developed to induce minute quantity of electric current to the calli. Electric current of 1µA and 2µA was applied to the system continuously as well as for an interval of 1 h day-1 for a month and differences in callus mass before and after treatment were observed. Callus induced with electric current of 2 µA continuously for a month had maximum weight gain followed by callus induced with 1µA current continuously for a month. Here, anode and cathode were inserted into media and callus respectively. In other two treatments where, 1 µA and 2 µA current was inducted into callus for an interval of 1 hday-1 for a month as well as in control where no current was induced significant weight gain was not observed. The study implicates the effect of electric current in cell division of plants and the results suggests that continuous application of weak electric current in range of 1 and 2 µA enhances callus growth in plumular explants of coconut and could be used as a novel strategy for callus multiplication of coconut, a monospecific crop recalcitrant to in-vitro culture.
Background: Cryopreservation opens new avenues in the field of genetic resource conservation, esp... more Background: Cryopreservation opens new avenues in the field of genetic resource conservation, especially in recalcitrant seeded palms such as arecanut for which field genebanks are exposed to pest and disease attacks and natural calamities. It is only through cryopreservation that the safety of the conserved germplasm can be assured at a relatively low cost for extended periods. Objective: The objective of this work was to standardize various aspects of arecanut pollen cryopreservation, viz. collection and desiccation of pollen, in vitro germination, viability and fecundity studies. Materials and methods: Pollens of three arecanut genotypes (Sumangala, Hirehalli Dwarf and Hirehalli Dwarf x Sumangala) were collected in December 2013-February 2014. In vitro viability tests were conducted using fresh and desiccated pollen. Desiccated pollen was cryopreserved by direct immersion in liquid nitrogen and cryostored for different durations (24 hours to 2 years). Viability and fertility studies were conducted using cryopreserved pollen. Results: Pollen extraction was achieved from fully opened male flowers by desiccation at room temperature (33-34 degree C). A medium containing 2.5 g/L sucrose was found to be best for in vitro germination at room temperature. There was no significant difference in germination between desiccated and cryopreserved pollen whereas pollen tube length decreased significantly after cryopreservation. Fertility studies using HD x Sumangala pollen cryostored for various durations (1 month, 1 year and 2 years) showed the setting of 70, 43 and 62%, respectively. Normal nut set was observed using cryopreserved pollen. Conclusion: Pollen cryopreservation is a viable option for germplasm conservation and hybridization programmes in arecanut.
Random Amplified Polymorphic DNA (RAPD) is a simple technique used for genetic analysis in many c... more Random Amplified Polymorphic DNA (RAPD) is a simple technique used for genetic analysis in many crops. The effectiveness of 45 RAPD primers were evaluated based on polymorphism information content (PIC) and marker index (MI) for their use in coconut. Among the RAPD primers, maker index ranged from 6.280 to 0.031. The primer OPBE 06 had the higher MI and accordingly other primers were ranked. Five, 10 and 15 primers were identified as informative primers. The dendrograms were constructed separately for informative primers and 45 primers using software NTSYS pc. The dendrogram obtained using 15 informative primers was comparable to that of 45 primers.
Coconut zygotic embryo culture has practical value in collection and exchange of germplasm overse... more Coconut zygotic embryo culture has practical value in collection and exchange of germplasm overseas and is done on different media protocols. Differences in plantlet survival and media composition led to a study with an objective to compare growth, leaf gas exchange characteristics and biochemical constituents of plantlets of dwarf and tall cultivars of coconut grown on four media viz., PCA-ARC, UPLB, IRD and CPCRI. A total of 960 embryos from two dwarf (COD and MYD) and two tall (WCT and LCT) cultivars of coconut were inoculated on four different media. The dwarfs germinated earlier than the talls. Maximum vitrification was observed in liquid media, viz. PCA-ARC followed by UPLB and IRD. At the time of transplantation to pots for acclimatization, plantlet morphological growth did not vary significantly. However, biochemical composition (reducing sugars, starch, total carbohydrates, free amino acids and proteins; the chl. a, b, total chlorophyll and chl. ‘a/b ratio’) of seedling leaves varied with cultivar and influenced by medium composition. Development of photosynthetic system was influenced by the composition of medium and readily usable carbon source in media seems to inhibit Pn. In general, plantlets raised on PCA-ARC and CPCRI media had higher in vitro and ex vitro survival rates followed by those raised on UPLB medium. Plantlets from IRD medium had lowest survival capacity. LCT and MYD plantlets survived better when grown on PCA-ARC medium, and WCT and COD plantlets survived better when raised on CPCRI medium. It is suggested that providing solid germinating medium to reduce vitrification loss; addition of auxins and reduction of salt concentrations in growth medium, reduction of sucrose concentration in rooting medium and gradual increase in PAR during rooting may help in early establishment of photosynthetic mechanism and better growth to increase the in vitro and ex vitro survival rates of coconut seedlings.
Vivipary is a problem in some dwarf varieties of coconut as their seed nuts show low germination ... more Vivipary is a problem in some dwarf varieties of coconut as their seed nuts show low germination compared to Talls. An experiment was carried out to study the extent of vivipary in dwarf coconut varieties (MGD, MYD, MOD and CGD) with WCT as control. Observations on nut traits like shape, colour, length, weight and water content of the seed nut, thickness, weight and polyphenol content of the husk, length and weight of embryo, TSS of nut water were recorded from 10-, 11- and 12-month-old nuts of each variety. Observations were also recorded at bimonthly intervals during November 2011-September 2012. None of the ten-month-old seed nut exhibited vivipary. However, few 11th old MOD nuts (3%) harvested during November showed vivipary. The results showed that the extent of vivipary was highest during September and least during January. Among the varieties, MYD exhibited maximum vivipary (24%) followed by MOD and MGD (16%) and the least was in WCT (0.6%). Vivipary was negatively correlated with various nut characters, husk thickness and weight. However, prevailing climatic conditions like amount of rainfall, number of rainy days and relative humidity during the preceding 30-day of harvest had significant positive correlation with vivipary. It is suggested that vivipary in dwarf varieties can be avoided by harvesting the seed nuts at the proper stage.
International journal of Bio-resource and Stress Management, Sep 30, 2022
The study was carried out at the Biotechnology Laboratory, Division of Crop Improvement, ICAR- Ce... more The study was carried out at the Biotechnology Laboratory, Division of Crop Improvement, ICAR- Central Plantation Crops Research Institute, Kasaragod during 2019−2021 to investigate the effect of electric current induction in coconut plumular callus obtained from WCT variety of coconut. Callus induction was observed when the plumules extracted from the embryo were inoculated into Eeuwens Y3 media supplemented with 16.5 mg l-1 2,4-D and 1 g l-1 activated charcoal. An electrical induction set up was developed to induce minute quantity of electric current to the calli. Electric current of 1µA and 2µA was applied to the system continuously as well as for an interval of 1 h day-1 for a month and differences in callus mass before and after treatment were observed. Callus induced with electric current of 2 µA continuously for a month had maximum weight gain followed by callus induced with 1µA current continuously for a month. Here, anode and cathode were inserted into media and callus respectively. In other two treatments where, 1 µA and 2 µA current was inducted into callus for an interval of 1 hday-1 for a month as well as in control where no current was induced significant weight gain was not observed. The study implicates the effect of electric current in cell division of plants and the results suggests that continuous application of weak electric current in range of 1 and 2 µA enhances callus growth in plumular explants of coconut and could be used as a novel strategy for callus multiplication of coconut, a monospecific crop recalcitrant to in-vitro culture.
Uploads
Papers by anitha karun