Population and single plant-derived inbred line analyses for sex expression in summer squash (cucurbita pepo l.)‎ Cv 'eskandrani'

Abstract EN

Literature have shown large agreement on the notion that enhanced formation of pistillate flowers increases the yield of immature fruits in summer squash (Cucurbita pepo L.).

However, selection scheme to improve sex expression is not adequately clarified in our local favorable cv ‘Eskandrani’.

Our initial assessment in an open pollinated population grown in summer and winter seasons showed the existence of discrete group of phenotypes that is largely influenced by environmental factors.

The χ2 test of phenotypic distribution in open pollinated population suggested fitness to 2 dominant major genes controlling sex expression.

Based on progeny test in the first selfed generation, one line homozygous for maleness was obtained and four heterozygous balanced monoecious lines were identified.

The latter lines showed 3: 1 segregation ratio for balanced monoecious phenotype and predominant pistillate flower producing phenotype, respectively.

These lines consistently behaved as heterozygous balanced monoecious phenotype up to the third generation.

Increasing tendency to femininity was associated with lowered node of the first female flower and reduced stem length and number of leaves.

Immature fruit yield trial conducted during summer and winter seasons indicated superiority of the four balanced monoecious lines to the open pollinated population and the inferiority of the line producing predominantly staminate flowers.

This study suggests the feasibility of complete elimination of maleness phenotype in summer squash cv ‘Eskandrani’ by line breeding and the significance of correlated response with improved sex expression to enhance crop earliness and elevate immature fruit yield.