GENERATING GENETIC DIVERSITY THROUGH DIALLEL CROSSES OF PROMISING POTATO CULTIVARS (Solanum tuberosum L.) AND STUDYING CULTIVAR HYBRIDS UNDER WATER DEFICIT STRESS

Abstract

This research was conducted from 2017 to 2018 to produce genetic diversity and examine selected suitable hybrids concerning certain agricultural traits under normal and water-deficit stress conditions in a Zarghostar-Arta company. In 2017, four potato cultivars, namely, Luca, Banba, Esprit, and Agria, were crossed as parents via mutual hybridization based on the diallel method guided by Griffing’s method III. About 8550 true potato seeds were produced, among which 3944 seeds were germinated, and 151 hybrids were selected for culturing on a split-plot with a randomized complete block design involving three replications. The main factors of interest in the design were three irrigation levels (100%, 85%, and 70% water supply requirements), and the sub-factors were 12 populations. The highest specific combining ability for tuber yield was found in the direct cross of the ♂Luca×Esprit♀ compound under normal and mild conditions. In mild and severe stress conditions, the hybrid of ♀Luca×Agria♂ and the direct cross of the ♀Luca×Esprit♀ compound had the highest tuber yields. The general heritability of tuber yield ranged from 81.68% (in 70% available water) to 94.66% (in 100% available water), and the specific heritability ranged from 62.39% (in 85% available water) to 86.78% (in 100% available water). Additive variances in the varieties were 118.05, 46.92, and 37.49, and dominance variances were 33.82, 8.97, and 0.68 in 100%, 85%, and 70% available water, respectively.