Litchi

Litchi (Litchi chinensis Sonn.) is a tropical fruit characterized by a rapid pericarp browning and dehydration during postharvest, resulting in an accelerated shelf life and in a loss of consumer appreciation and consequently of its market value. The aim of our study was to assess litchi fruit chemical-physical and sensory quality changes during postharvest and shelf life using rapid refrigeration (RR) and active modified atmosphere packaging (MAP). Litchi fruits were picked at commercial harvest and were divided in 4 groups: not treated fruit (CTR); rapid refrigerated fruit (RRF); modified atmosphere packed fruit (MAP); hydrogen peroxide treated and modified atmosphere packed fruit (MAP+). CTR and RRF fruit were packed in microperforated plastic bag whereas MAP and MAP+ fruit were packed in unperforated high-density polyethylene package in which a gas mixture (60 kPa N2, 30% CO2 and 10 kPa O2) was flushed and then the bag was hermetically sealed. RRF, fruit were submitted to cooling in order to rapidly reduce their temperature using a blast cabinet which allows to reach 4° C in 15 minutes in three different steps. Finally, all the treated fruit were submitted to cold storage (5°C) for 12 days. Chemical-physical and sensory characteristics were analyzed after 4, 8 and 12 days of cold storage and their shelf life was monitored after 2 and 4 days at 20° C. Generally, the fruit submitted to RRF treatment presents a more intense red color in particular referring to L parameter and the best chemical-physical characteristics. Moreover, RRF fruit revealed having more consistency, juicy flesh, fruity flavour and exotic flavour after 4 days and of fruity odor and exotic odor after 8 days of cold storage. After 12 days, MAP and MAP+ showed a sensory decay. Finally, RRF technique, by rapid refrigeration, permits to prolong fruit color and taste during cold storage and consequent shelf life.

In this investigation, multiple shoot formation using nodal explants of3-4 year old litchi trees is reported which could pave the way for clonal propagation of litchi from identified elite, adult identified trees in future. Multiple shoot formation was obtained on modified Woody Plant Mediurn. A continuous proliferating shoot culture was established by repeatedly sub-culturing the original nodal explants on shoot multiplication medium after each harvest of newly formed shoots. The shoots were separated and planted on several media for rooting as this is a perpetual problem with many tree species. This was overcome by giving a pulse treatment to the cut ends of rnicroshoots with IBA (100 mM) in MS liquid medilllll for 15 min. The shoots were implanted on MS semi solid medilllll supplemented with IBA (20.6 MM) and litchi seed powder (1 g L _,)for rooting. This novel approach promoted rooting of shoots in vitro. Well established plantlets were successfully transplanted to the nursery after hardening.

Litchi (Litchi chinensis Sonn.) is an introduced crop in India and has limited genetic variability characterized by
differences in flushing pattern, leaf, panicle and fruit traits. Molecular markers were employed to expose the genetic
diversity of 20 litchi cultivars from the Indian peninsula and facilitate documentation of the native germplasm diversity.
Efficiency of individual primers was evaluated on the basis of average band informativeness and resolving power,
where random oligonucleotide markers OPA-5 and OPA-3 scored best. Among tested microsatellite markers, ISSR
01 and 13 had high values for primer efficiency and these were found to supplement simple sequence repeats for
generation of cultivar barcode and clustering analyses. Efficiency of microsatellites (Simple Sequence Repeats and
Inter Simple Sequence Repeats) was established by high values for polymorphism (0.691), diversity index (0.264),
effective multiplex ratio (48.8470) and marker index (12.896), thus reiterating its potential as for developing barcodes
for cultivar identification and conservation. Phylogenetic analysis based on RAPD and microsatellites revealed
clustering of the cultivars into four major groups, although within a very narrow range (0.63 - 0.90) of similarity, viz.
Seedless (i.e. Bedana), Mandarji, Shahi and China groups. The clustering followed grouping based on fruit morphology,
leaf and panicle attributes disagreeing with earlier views regarding incongruity of clustering pattern with morphological,
ecological and climatic adaptations. Discrimination of cultivars like Dehrarose and Dehradun, being often labeled as
synonyms, was also done. Interestingly high polymorphism and low gene diversity have been exposed by molecular
markers, commenting on narrow genetic background of litchi cultivars from India.