Use of phenotypic markers to determine the genetic variability of some local and tissue cultured date palm Phoenix dactylifera L. cultivars

Abstract

This study was conducted during the growing season (2024) in one of the private orchards in Nasiriyah district, the center of Dhi Qar Governorate, at longitude (46.06) and latitude (31.90) on some date palm cultivars produced by tissue culture and their counterparts grown by the offshoots method (the traditional method). The aim of studying the phenotypic description (vegetative, floral and fruit) of the studied cultivars, which are (local Barhi and produced by tissue culture, local Balka and produced by tissue culture, local Sukkari and produced by tissue culture), in addition to the cultivars produced by tissue culture only (Khalas, Saqai and Majhool). Results of the phenotypic indicators (vegetative, floral and fruit) and the total chlorophyll content of the leaves showed that the local Barhi cultivar was superior in the average traits (the length of the leaves, the number of fronds, the number of thorn , the length of  the thorn , the length of the  thorns area, the length of the fronds area, the width of the leaf base, the diameter of the trunk, the number of spadix, Length of the spadix, the width of the spadix, panicle weight, number of flowers, fruit stalk length, fruit panicle length and fruit diameter), while the Barhi produced by tissue culture cultivar recorded the highest rate for the two traits (percentage of frond area and the length of fruit panicle), the Balka produced by tissue culture cultivar recorded the highest rate for the trait of percentage of frond,  The local Balka cultivar recorded the highest rates for the following traits (frond length, thorn length, total chlorophyll, fruit length, and fruit cap height), while the local Sukkari cultivar recorded the highest rates for the traits (frond width, total chlorophyll, and number of spadix), the Khalas produced by tissue culture cultivar recorded the highest rate for the trait (thorn length), the Majhool produced by tissue culture cultivar recorded the highest rates for the following traits (thorn length, thorns area percentage, total chlorophyll, number of spadix, fruit diameter, fruit and seed weights, fleshy layer, and fruit size), while the Saqai produced by tissue culture cultivar recorded the highest rates for e traits (frond length, frond area percentage, number of panicles, fruit diameter, fruit weight, fleshy layer weight, and fruit size). The results of tree cluster analysis of phenotypic traits among studied cultivars showed that cultivars were distributed into two groups, the first group included cultivars (Saqai produced by tissue culture, local Balka, local Sukkari, local Barhi and produced by tissue culture), while the second group included cultivars (Sukkari, Majhool, Balka and Khalas produced by tissue culture). The Sukkari produced by tissue culture cultivar recorded furthest genetic distance of (14.2%), thus it is furthest genetically from the rest of studied cultivar. The percentage of genetic similarity between local Barhi and produced by tissue culture cultivar reached (100%), and between the local Balka and produced by tissue culture cultivars reached (99.9%). The results showed by analysis the main ingredients of variation of the appearance qualities that there are a range of appearance traits (Vegetable, floral and fruity) can be used to distinguish between the different cultivars of dates palm most important (The length of the fruity panicle , number of panicles, fruiting stalk length , panicle weight, number of flowers, spadix width, fruit diameter, number of spadix , leaf base width, spadix length, thorns area length, seed and fruit weights, the weight of the flesh layer, the length of the fronds area, the diameter of the trunk, number of  thorns , the size of the fruit, fruit cap height, number of fronds, fruit length, the ratio of the fronds area, the ratio of  the thorns area, the length of the frond and the width of the frond), which represents these traits (85.13%) of the total variation.