RESPONSE OF THREE CYCLES OF S1 RECURRENT SELECTION FOR GRAIN YIELD IN MAIZE POPULATION SAKHA 14

The new white composite maize population Sk14 was developed in Sakha Research Station, Egypt. This population which showed heterotic behavior was subjected to three cycles of S1 recurrent selection to improve yielding potentiality. The three cycles were made during the period from 2010 to 2018. The original cycle, Sk14 C0 and three cycles of selection, Sk14 C1, Sk14 C2 and Sk14 C3 and two populations Gz-2 and AED as checks were evaluated at four locations for grain yield during 2020 season. The phenotypic, genotypic, genotypic × environment interaction variances, broad sense heritability and the expected genetic gain% for Sk14 C1 were higher than Sk14 C2 and Sk14 C3, indicating that the genetic variability was decreased with advanced cycles of selection. Grain yield increased linearly during three cycles of the S1 recurrent selection, the highest mean obtained in C3 followed C2, C1 and C0. The higher percentage gain cycle-1 was realized in C3 than C0 (14.33%) followed C3 than C1 (9.06%) and C3 than C2 (8.44%), indicating that the S1 recurrent selection employed was effective in improving grain yield. The population Sk14 C3 had the highest grain yield and most stable population based on 4 (CV%, bi, Pi and Si(1)) out of 5 parametric stability statistics, this meaning that this population could be used in maize breeding program as source for deriving maize inbred lines of tolerance to different production conditions.