A correlation based response parameter proposed for varietal promotion/identification in coordinated varietal evaluation trials: A case study in bread wheat (Triticum aestivum L.)

Abstract

A parameter based on correlation coefficient between deviations of yields of a variety from corresponding mean yields recorded at several locations, and the estimates of similar deviations for a check variety was used to estimate response of each of the 44 varieties included in National Initial Varietal Trial - Irrigated Timely Sown, Coordinated Trial of bread wheat planted in North Western Plains Zone and North Eastern Plains Zone during 1999-2000. Five well established standard check varieties were also included in the trial for comparison. The deviations in the yields of test entries from mean yield of all the test entries and the checks were computed for each location. The correlations between deviations of the yields of a variety and those of each of the checks were treated as measures of sensitivity or response. Significant positive correlation was taken as a measure of similarity between a variety and a check included in the pair while recommending variety for promotion or identification. This response estimate of a variety can be used as an additional parameter along with yield potential and other desirable characteristics conventionally used. Only thirteen test entries exhibited similarity in response with the five check varieties used. In the given example two varieties HD 2790 and WH 736 should have been promoted to the next trial of higher order on being statistically identical in sensitivity with standard check varieties HD 2329 and HP 1731, respectively. The variety HD 2790 was also statistically at par to the best check PBW 343 and superior to all other checks in yield (qlha). Similarly variety WH 736 was significantly superior to all checks other than PBW 343 in yield. The five check varieties differed In sensitivity to varying agroecological conditions. The check variety HUW 206 exhibited most co-adaptive nature and had similarity with three test entries UP 2527, WH 738, RW 3542 and a filler entry in sensitivity towards different levels of agronomic management used at different locations.