Response of root characteristics and yield in peanut under terminal drought condition

Drought at pod filling reduces growth, yield, and seed quality of peanut (Arachis hypogaea L.) Great root system can reduce yield loss under water stress. There is a lack of information on root traits for peanut genotypes and the relationship between rooting traits and peanut yield under terminal drought. The pot experiments were conducted at Khon Kaen University, Thailand, in 2004-2005 and 2005-2006. A randomized complete block design was used with two factorials set-up with four replicates. Factor A consisted of two water regimes (field capacity and 1/3 available water at 80 d after planting to harvest), and factor B comprised of 11 peanut genotypes. Data were recorded for root traits (root dry weight, root length, root surface, root diameter, and root volume), and peanut yield (pod dry weight, biomass, and harvest index) were measured at final harvest. Terminal drought significantly decrease root characteristics (0.83-1.03 g plant(-1) of root dry weight) and peanut yield (7.98-8.89 g plant(-1) of pod dry weight). Yield responses to terminal drought were not correlated with root traits except root length and root volume (r = 0.71** and 0.83**, respectively). Some genotype, root traits seem to be correlated With peanut yield under terminal drought. 'KK60-3' showed high root traits, maintained pod dry weight under terminal drought, whereas Tifton 8 maintained biomass production. ICGV98348 had high root traits, maintained pod dry weight and harvest index under drought conditions. The results suggested that peanut contained high root characters which maintained yield under terminal drought.