International Journal of Agricultural Science Research Vol. 6(3), pp. 011-017, July 2016 ISSN 2327-3321 ©2017 Academe Research Journals

Full Length Research Paper

Sorghum populations’ improvement

Abubaker A. Abdallah* and Abdelbagi M. Ali

Agricultural Research Corporation, Biotechnology and Biosafety Research Center, Khartoum, Sudan P. O. Box 30. Sudan.

*Corresponding author. E-mail: abubakeraam@yahoo.com.

Accepted 12 December, 2016

Abstract

The objective of this study was to increase the outcrossing rate and yield potential for improve advance heterotic Sorghum bicolor (Linn.) Moench, Caudatum-race populations with high heterozygosity using recurrent selection (RS) and SSR markers as a tool for improve new sorghum breeding material. One hundred accession chosen for their early flowering and maturity were intermitted using random-mating system in an isolated crossing block for duration period of four recurrent selection cycles over main and off-season respectively. The selections were based on detection of polymorphism at seedling stage among populations. All established plants were sampled at the two-leaf stage for DNA extraction. Leaf tissue taken from 3200 plants (32 plants / accession) was genotyped using SSR markers and the highest 200 polymorphic plants were selected as parents for RS cycle_1. This procedure was repeated in three subsequent cycles. Fifteen genomic SSR markers were used in different combinations of duplex and triplex PCR. Genotyping data from five microsatellites loci were used to estimate outcrossing rate in each cycle by MLTR program. The outcrossing rate increased after four cycles of recurrent selection from 8% to 9%, 19%, 34% and 48% from C₀ to C₄ populations respectively. The progenies from recurrent selection were evaluated for genotypic and phenotypic variance under rainfed and irrigated different environments. The results revealed high significant change in observed heterozygosity which is confirmed superior and positive effect of heterozygosity on grain yield and some agronomic traits. Broad sense heritability was high for most of traits under study. High significant and positive correlation of outcrossing observed with some traits especially head diameter and head shape, reflects the direct effect of outcrossing through RS cycles and the increased outcrossing confirms that selection for grain yield and yield components could be achieved through selection of multi-locus individuals within populations. The study revealed the usefulness of the markers in accelerating the selection process and increasing the efficiency and accuracy of constructing heterotic populations that are expected to have more breeding advantage over the base population.

Key words: Heterotic, sorghum, population, improvement.