Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 29, 2011
Publication Date: August 11, 2011
Citation: Zeng, L., Meredith Jr, W.R. 2011. Relationships between SSR-based genetic distance and cotton F2 hybrid performance and heterosis. Crop Science. 51:2362-2370. Interpretive Summary: The market of cotton hybrid production has great potential. Evaluation and selection of parents are important for maximizing hybrid yield and fiber quality, but cost is high. Prediction of hybrid performance by analyzing parents using DNA markers may promote the utilization of hybrids in cotton production by saving time and costs. This study was designed to analyze the genetic make-up of cultivars and exotic germplasm lines by DNA markers, and their relationships with respect to performance of the hybrids derived from these lines. The results show that DNA marker characterized genomic information can be used to select and array parents from germplasm resources in crosses. The performance of hybrids derived from marker-arrayed parents can be predicted and improved.
Technical Abstract: Analysis of relationship between genetic distance and hybrid performance may promote the utilization of exotic germplasm in hybrid production. This study was designed to determine the relationship between SSR based genetic distance (GD) and F2 hybrid performance in cotton (Gossypium hirsutum L.). Forty-eight F2 hybrids derived from crosses between four elite germplasm (EL) lines and twelve exotic germplasm lines, i.e., six Species Polycross germplasm (SP) lines and six ‘John Cotton’ germplasm (JC) lines, were evaluated in four environments during 2008 and 2009. Lint yield and fiber properties in the F2 hybrids were diverse. Wide ranges of mid-parent heterosis (MPH) were identified among the 48 F2 hybrids for all traits. One hundred and fourteen primer pairs amplified 284 polymorpic fragments among the 16 parental lines. Parents divided into three groups in a dendragram of UPGMA clusters based on pair-wise GD among parents. The correlations between GD and F2 performance were significant for some fiber properties, but low with the highest r value in fineness (r=-0.43). The highest correlation between GD and MPH was -0.43 for short fiber content. Population differentiation (P<0.001) was identified between JC and EL, but not between SP and EL. Moderate correlations with r values ranging from 0.42 to 0.62 were detected between GD and fiber properties in the JC-derived F2 hybrids, but not for the SP-derived F2 hybrids. The moderate correlations between GD and the performance in the JC-derived F2 hybrids appeared to be attributed to the additive gene effects from the genetically differentiated germplasm groups. The results suggest difficulty in prediction of hybrid performance by GD in cotton. However, better prediction of F2 performance by GD may be expected when crosses are made between parents from genetically differentiated groups in cotton germplasm.