Naturally and Artificially Drought-Induced Small-Plants within the Pure-Line Runner-Type Peanut Cultivar ‘Georgia-10T’

Abstract

During 2011 at Tifton and Plains, GA, there was an early-season drought stress period during May and June. A few drought-tolerant plants were identified and tagged which appeared green and turgid amongst otherwise dry and severely-wilted plants within the pure-line, runner-type peanut (Arachis hypogaea L.) cultivar, ‘Georgia-10T'. Pod and seeds were harvested from these drought-tolerant individual plant selections (IPS) for increase and testing. During autumn and winter of 2014 to 2015, a greenhouse drought study was utilized to test these IPS's compared to the parental check cultivar. Green and turgid plants were identified within the same check cultivar after exposing the plants to an early-season two-wk drought stress period at 60 and 90 d after planting. Seed from IPS of naturally occurring and artificially drought-induced plants produced similar normal and small-plants. Replicated preliminary yield tests were conducted during 2017 to compare progeny rows from these IPS's to the check cultivar, Georgia-10T. Field trial data indicated that the smaller-plants produced from early-season drought stress had significantly reduced yield, grade, pod size, and seed size as compared to larger plant selections and Georgia-10T parental cultivar. In a greenhouse study conducted during autumn and winter of 2017 to 2018, these small plants had significantly shorter internode length and mainstem height compared to the same small plants treated with gibberellic acid (GA3) which were taller and had longer internode lengths after one and two months. Small plants resulted from artificially and naturally occurring early-season drought-induced stress within the pure-line runner-type peanut cultivar, Georgia-10T, were caused by lack of GA3. The normal and small-plants each have bred true-to-type following several self-generations. The ramification of these findings suggest the importance of early-season irrigation, especially for seed production of peanut cultivars to avoid subsequent development of low-yielding, small-plants induced by drought-stress.