Heritability estimates, genetic correlation, and identification of RAPD markers linked to seedling vigor and associated agronomic traits in sorghum
Abstract
Seedling vigor in sorghum (Sorghum bicolor (L.) Moench), is important for improving stand establishment. These studies were conducted to investigate the heritability of the difference in seedling vigor observed between SRN39 and Shanqui red, to assess the genetic relationships of seedling vigor with field performance and phenolic compounds concentrations, and to identify QTLs associated with these characters. One hundred recombinant inbred lines and their parents were evaluated for seedling vigor, crop performance and phenolic compounds concentrations. Percent seed germination at 12$\sp\circ$C and at 22$\sp\circ$C, seedling emergence, seedling height and shoot dry weight were determined under controlled environments. Significant genetic correlation between different estimates of seedling vigor were observed. Germination at 22$\sp\circ$C, emergence, seedling vigor scores, and the rate of seedling dry matter accumulation were significantly correlated with grain yield. High phenolic concentrations were associated with vigorous seedlings, high percent germination at 22$\sp\circ$C, high emergence, and taller seedlings. Only total phenols were significantly associated with grain yield. Lines with a red coleoptile tended to be more vigorous and more productive than lines with a green coleoptile. RAPD markers on linkage groups D and F were significantly associated with seedling vigor scores. Germination at low and at optimum temperatures were mostly under different genetic control. The marker analysis showed that the visual scoring system used was effective in integrating germination, emergence, and seedling height. It was concluded that Shanqui red could be a valuable parent for the development of early maturing varieties that have improved stand establishment, and adapted to environments where low temperatures at planting in spring and early frost in the fall prevail. The identification of markers associated with seedling vigor and field performance should make breeding for the improvement of these traits more efficient, by minimizing the amount of genotype by environment interaction effect.
Degree
Ph.D.
Advisors
Ejeta, Purdue University.
Subject Area
Agronomy|Genetics
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