Background:
Higher seed yield is one of the objectives of jatropha breeding. However, genetic analysis ofthe yield traits has not been done in jatropha. Quantitative trait loci (QTL) mapping wasconducted to identify genetic factors controlling growth and seed yield in jatropha, apromising biofuel crop.
Results:
A linkage map was constructed consisting of 105 SSR (simple sequence repeat) markersconverged into 11 linkage groups. With this map, we identified a total of 28 QTLs for 11growth and seed traits using a population of 296 backcrossing jatropha trees. Two QTLsqTSW-5 and qTSW-7 controlling seed yield were mapped on LGs 5 and 7 respectively, wheretwo QTL clusters controlling yield related traits were detected harboring five and four QTLsrespectively. These two QTL clusters were critical with pleiotropic roles in regulating plantgrowth and seed yield. Positive additive effects of the two QTLs indicated higher values forthe traits conferred by the alleles from J. curcas, while negative additive effects of the fiveQTLs on LG6, controlling plant height, branch number (in the 4th and 10th months post seedgermination), female flower number and fruit number respectively, indicated higher valuesconferred by the alleles from J. integerrima. Therefore favored alleles from both the parentscould be expected to be integrated into elite jatropha plant by further backcrossing andmarker assisted selection. Efficient ways to improve the seed yield by applying the two QTLclusters are discussed.
Conclusion:
This study is the first report on genetic analysis of growth and seed traits with molecularmarkers in jatropha. An approach for jatropha improvement is discussed using pleiotropicQTLs, which will be likely to lead to initiation of molecular breeding in jatropha byintegrating more markers in the QTL regions.Source:
http://www.biotechnologyforbiofuels.com/rss/