Variation in Transpiration Efficiency and Its Related Traits in Valencia Mapping Population ICGV 7243 X Valencia-C.

Transpiration efficiency (TE) has been considered as an important component for water use efficiency (WUE) and to screen yield variation under drought stress in peanut. A Recombinant Inbred Lines (RIL’s) for Valencia breeding were developed for high WUE from two contrasting parents differed in their drought tolerance. A set of 112 RILs derived from drought tolerant ICGV7243 and drought susceptible Valencia-C were used along with parents to evaluate TE and pod yield. A lysimetric system was used to grow the plants and to screen the RILs for their water use, dry weight, TE, pod yield and haulm weight. One experiment was conducted during December, 2015 to March 2016 using randomized complete block design with 4 replications. Plants were subjected to drought stress treatment, imposed from 30 days after sowing in the form of an intermittent stress, i.e. the plant were subjected to cycles of drying and re-watering similar to treatments applied under field conditions. A 2 fold variation for TE was observed among 112 RILs derived from drought tolerant and susceptible parents. Other parameters pod yield, water use and haulm weight showed significant variation among the RILs. A significant association was observed between TE and seed yield in this study, although the coefficient of variation was relatively weak (R² = 0.14), which was also quite typical of mild vapor pressure deficit environment. The distribution of TE among the 112 RILs indicates polygenic character of TE controlled by dominant and additive genes. This study further requires quantitative trait loci (QTL) analysis for marker assisted selection to select and breed efficient genotypes for improved TE.