Genotypic Sensitivity to Irrigation Treatments and Yield Potential of Four Peanut Cultivars.

Peanut is the most widely cultivated legume crop worldwide. Water is limited to most peanut growers worldwide and untimely rainfall can make it much worst. Screening for drought tolerant lines that can withstand short spells of drought during a growing season will benefit growers from yield loss. However, the unavailability of reliable tools to screen peanut genotypes for drought tolerance are the major hurdles in the genetic improvement of peanut for drought tolerance. A field study was conducted near Brownfield, Texas in 2009 and the same is repeated during 2010 to compare four peanut market types namely Valencia – C (Valencia market type), ICGS-76 (Virginia market type), C76-16 (Runner market type) and COC-41 (Spanish market type). Two irrigation treatments were applied during the growing season a.) conventional watering at every 10 days (40 mm) and b.) stress treatment watering every once in two weeks (40 mm). The design of the experiment was randomized complete block with 4 replications. Each plot was planted on a raised bed with 100 cm row spacing. The seed rate was 20 seeds for one meter row length. In 2009 ICGS -76 and C76-16 gave higher yields compared to Valencia – C and COC-41 under both the irrigation treatments. There was no significant difference among the four varieties with respect to grade. We employed a combined transcriptomics and proteomics approach to study the primary transcriptional networks and functional proteins involved in the drought tolerance.  Transcript level changes were detected by high density (8 x 15k) peanut microarrays, while one- and two-dimensional gel electrophoresis detected large number of differential proteins, with an obvious skew towards signaling and cell wall strengthening. Some of these identified proteins and their corresponding genes could contribute a physiological advantage under drought, making them potential candidates for marker-assisted breeding.