Genetic action and the amount of dominant and recessive genes in upland cotton

Abstract

A nine parents diallel of upland cotton was planted in a randomized complete block design with three replication. Data collected from the diallel where used to estimate genetic parameters to exploiting of the gene action according as (Hayman,1954) method and finding intercept of unit slope line and the Vxi values corresponding to two points were parabola is cut by this regression line and dividing the distance between those points in to four equal parts are investigated and estimated the exact amount of dominant and recessive genes for each parent was introduced. The results showed that mean square of genotypes highly significant for all traits . The dominant genetic variance was more important than additive one , average degree of dominance was greater than one for all studied characters . The values KDKR indicate to increase of dominant gene in the parent, and the value of pq was decreased 0.25 that show unregulated distribution for alleles . Heritability was arranged from 14% for seed cotton yield to 22% for boll weight .the Lachata parent was showed highly amount of dominant genes 81.11% for boll weight ,86.32% for number of bolls per plant and 88.18% for seed cotton yield. This results also revealed Lachata variety exceeded on for all studied varieties in seed cotton yield 116.8 gplant , boll weight 4.6 g and number of boll per plant 27.8 .