%0 Journal Article
%T Construction of Genetic Linkage Map and QTL Analysis of Sink-Size Traits in Pearl Millet (Pennisetum glaucum)
%A V. Vengadessan
%A K. N. Rai
%A J. R. Kannan Bapu
%A C. T. Hash
%A R. Bhattacharjee
%A S. Senthilvel
%A M. T. Vinayan
%A T. Nepolean
%J ISRN Genetics
%D 2013
%R 10.5402/2013/471632
%X A linkage map, primarily based on SSCP-SNP markers, was constructed using 188 F2:3 mapping population progenies produced from a cross between two pearl millet inbred lines having diverse parentage. The skeleton linkage map covered 1019£¿cM and it comprised of 44 markers distributed across the seven linkage groups. Average adjacent-marker intervals ranged from 14£¿cM on LG1 to 38£¿cM on LG6, with an overall mean of 23£¿cM. Using the F2 linkage map and phenotypic data from the F2 and F2:3 generations of the mapping population, a total of 18 putative QTLs were detected for the three sink-size components. Eight QTLs explained 42.7% of observed phenotypic variation for panicle length using the F2:3 data set. For panicle diameter, 5 QTLs explained 45.8% of observed phenotypic variation. Similarly for grain size, 5 QTLs explained 29.6% of phenotypic variation. Genomic regions associated with panicle length, panicle diameter, and grain size were comapped on LG6 between Xpsms88 and Xpsms2270, indicating the existence of a gene or gene cluster. The QTLs for panicle length on LG2 and LG6 ( in both F2 and F2:3 data sets), for panicle diameter on LG2 and LG3 ( in the F2:3 data set), and for grain size on LG3 and LG6 ( in both F2 and F2:3 data sets) were identified as promising candidates for validation prior to possible application in marker-assisted breeding. 1. Introduction Pearl millet (Pennisetum glaucum (L.) R. Br., ) is a major cereal crop grown in the arid and semiarid tropical regions of Asia and Africa. It produces grains with high nutritive value even under hot, dry conditions, on infertile soils of low water holding capacity, where other cereal crops fail. This makes pearl millet a highly desirable crop for farmers in such harsh environments. Largely because of these harsh environments in which most of the pearl millet is grown, its average grain yield in Africa and Asia fluctuates between 500 and 600£¿kg ha£¿1, which is extremely low compared to other cereal crops grown in more favorable environments. Grain yield stabilization and improvement are of primary importance in pearl millet breeding programs. Grain yield is a function of total dry matter yield and harvest index, and enhancing the total dry matter yield and harvest index or both can increase grain yield. In general, harvest index can be increased by improving sink size and it has been demonstrated in many correlation studies that traits such as panicle size (length and diameter) and grain size have direct positive correlations with grain yield [1, 2]. Hence, enhancement of these sink-size component
%U http://www.hindawi.com/journals/isrn.genetics/2013/471632/