Rice plants alter their yield component parameters based on their tolerance to low temperatures determined by a non-invasive method during the vegetative stage

Abstract

The first rice phenological stages are commonly subjected to low temperatures(LT) in temperate crop areas. Here, plants of rice genotypes were analyzedaccording to their LT tolerance at seedling stage, using a realistic experimentaltemperatures range, and measuring quantitative and operator-independentparameters, fast-obtainable by non-invasive techniques. The ratios betweenvalues of these parameters determined in plants under LT condition with respectto the control condition were statistically analyzed. We have found a discriminantformula based on two parameters that allowed to differentiate betweengenotypes previously described as tolerant and sensitive to LT, with a very lowgeneral classification error. The application of the discriminant formula to scoreplants under LT, using all genotypes from the Rice Diversity Panel 1 whichcomprehensively represents the genetic variability of the O. sativa species,resulted in LT tolerance levels of its subspecies and subpopulations consistentwith previous reports. In turn, a strong association between the LT tolerancescore at the seedling stage and the panicle weight in plants under field LT duringthe vegetative stage, suggested that this scoring could be used as an indirectselection factor of genotypes with good yield traits and suited to LT proneenvironments.