Introgression of Pigment Gland Morphogenisis Delay into Upland Cotton: Potential of DNA Markers to Monitor Parental Contribution to Progenies
Dec 21, 2018
The delay of pigment gland morphogenisis in the seed confers to several Australian wild diploid cottons the glandless-seed/glanded-plant trait. To introgress this trait from G. sturtianum Willis (2m = 2x = 26, 2C1 genome) into G. hirsutum L. (2n = 4x = 52, 2(AD)1 genome), we used bridge crosses to synthesize two trispecies hybrids, G. hirsutum-G. raimondii Ulbrich – G. sturtianum (HRS) and G. thurberi Torado – G. sturtianum – G. hirsutum (TSH). Recurrent backcrossing of these hybrids to G. hirsutum produced progenies expressing the desired trait at different levels. The objective of this study was to assess the genomic contribution of the parental species to their progenies with random amplification polymorphic DNA (RAPD) and restriction fragment length polymorphism (RFLP) probes. The use of 30 decamer primers yielded 375 bands of which 339 were polymorphic between parents. Among 49 bands specific to the donor G. sturtianum, 20 and 18 that segregated in backcrosses, were observed in HRS and TSH, respectively. The American wild diploid species used as bridge showed 12 and 13 specific bands for G. raimondii (2n = 2x = 26, 2D5 genome) and G. thurberi (2n = 2x = 26, 2D1 genome), respectively. Genetic distances between G. hirsutum and the wild species involved in the cross were determined from RAPD data. This study allowed choice within backcross progenies those that shared the highest similarity to the cultivated cotton. The parental origin of chromosomes in the trispecis hybrids and the backcrosses were then identified using RFLP probes specific to cotton chromosomes. The results are discussed in relation to the expression of the desired trait.