GENETIC ANALYSIS OF TWO EGYPTIAN WHEAT CROSSES (Triticum aestivum, L.)

Abstract

Non-allelic interaction scaling test (A, B, and C) coupled with joint scaling test χ2 and six parameters model were applied to test the adequacy of genetic model and estimates the genetic components for days to heading, flag leaf area, (cm)2 number of spikes / plant, number of grains/spike, 1000-grain weight (g.) and grain yield plant (g.) using six generation (P1, P2, F1, B1, B2 and F2) of two wheat crosses; 1. sids1 X Gemmeiza 7 and 2. Gemmeiza 9 X Sakha 92, A randomized complete block design with three replications was used. The obtained results indicated the importance of additive genetic variance (D) in the genetic control of days to heading and flag leaf area for Gimmeiza 9 X Sakha 92 and number of spikes / plant in two crosses. Heritability in narrow sense was more than 0.50. While the dominance genetic variance (H) was found to be the prevalent type controlling for the remaining crosses in the studied characters and the value of (H/D)0.5 was more than one for these characters and heritability in narrow sense was less than 0.50. The non allelic interaction (A, B and C) coupled with joint scaling test (χ2) revealed that simple genetic model was adequate for explaining the inheritance of number of spikes/plant for Gemmeiza 9 X Sakha 92, epistasis played a great role of controlling remaining characters in two crosses. Additive (d) and additive X dominance (J) were significant for days to heading and number of grains / spike (1st and 2nd crosses), 1000 grain weight and grain yield / plant for 2nd cross. The digenic interaction type dominance X dominance (L) controlling days to heading (1st, and 2nd crosses), number of spikes/plant (1st cross), number of grains/spike, 1000-grain weight and grain yield / plant for 2nd cross. Understanding the type of gene action controlling mechanism of the yield and yield components couped with the reproduction system are considered the main limiting factors for choosing the appropriate breeding method. These information are of great interest for plant breeder to release high yielding wheat cultivars as well as early mature ones.