UTILIZATION OF MORPHOLOGICAL AND MOLECULAR MARKERS FOR ISOLATION AND CHARACTERIZATION OF OFF TYPES OF GIZA 86 EGYPTIAN COTTON

doi:10.12816/ejpb.2019.256677

UTILIZATION OF MORPHOLOGICAL AND MOLECULAR MARKERS FOR ISOLATION AND CHARACTERIZATION OF OFF TYPES OF GIZA 86 EGYPTIAN COTTON

Document Type : Original research

10.12816/ejpb.2019.256677

Abstract

Homogeneity and uniformity of yield and lint quality characters represented the practical criteria for identification and judging the purity of cotton cultivars. Thus, morphological and molecular markers were used to assess the genetic changes isolated from general farm from Giza 86 commercial variety. Eighteen spontaneous changes were isolated and selfed and thus evaluated with the original variety at Sakha Agriculture Research Station. Significant difference were obtained among Giza 86 standard variety and their off types for most studied characters, indicating the presence a lot of genetic variability .Moreover the off types differ among them . The original variety Giza 86 surpassed all the off types for all fiber characters and lint percentage. All the off types were inferior in lint percentage and all fiber quality characters, which showed decreased in lint percentage and sharply decreased in fiber length accompanied by decreasing in length uniformity with coarser and weaker lint. Some off types showed changed in lint color. The differences among the original Giza 86 variety and their off types were mainly affected by two factors, the first factor was due to the cultivar and their off types, and the second factor was concerning the ability of characters that might exhibited discrimination. The first six canonical varieties were significant (P < 0.01) and accounted for 98.2% of the among genotypes variance. The first canonical discriminate function which represented 78.1% of the total variability among genotypes with the largest Eigen value (95.126) is dominated by a large loading from degree of yellowness followed by fiber strength and fiber reflectance. The second function was largely affected by uniformity ratio which showed negative loadings and accounted for about 8.2% of the total variance among genotypes. Lint percentage followed by boll weight and lint strength showed the highest discrimination among genotypes at the third function. It is obvious that the genetic composition of Giza 86 compared to their off types chiefly differed in some characters such as degree of yellowness, fiber length, strength, lint percentage and micronaire reading. On besides, some characters showed high discrimination than the other. The standard variety Giza 86 and their off types, were grouped into ten major clusters according to the relative dissimilarity among them and contribution of the evaluated characters. The original variety Giza 86 formed a unique group with a wide divergent distance from the other off types. Twenty four out of 67 bands generated from all RAPD primer pairs were polymorphic and representing 35.82% of the total generated bands with an average 2.4 polymorphic bands per primer. The similarity coefficient matrix based on RAPD markers among the 19 genotypes ranged from 0.54 to 0.98. The dendrogram separated all genotypes into two major groups. The first group contained three off types, while the second groups consisted of the other off types with the original variety Giza 86 and can also be separated into eight sub clusters. Results from morphological measurements and DNA, RAPDs, markers are complementary factors for each other in studying and identifying the genetic variability and genetic diversity among genotypes and both gave essential information for understanding genetic variability in Egyptian cotton germplasm and provided a useful guide for conserving elite cotton germplasm and eliminate any spontaneous changes from commercial varieties during the multiplicities stages to maintain the uniformity and homogeneity of Egyptian cotton.

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