Mitochondrial Genome Diversity within a Cultivar of Daucus carota (ssp. sativus) Revealed by Restriction Fragment Analysis of Single Plants

Despite a fovourable environment during seed filling, ripening and harvest, and good storage conditions subsequent to harvest, there is variation for the ability of seeds of progeny of pearl millet (Pennisetum glaucum L.] R. Br.) composites to emerge under favourable conditions in pots, or in the field. Seedling emergence in pots and in the field was found to be a heritable trait in at least two of four composites that had not been specifically constructed for improvement of seedling emergence. The predicted genetic advance from selection for ability to emerge in pots is appreciable. From examination of genotypic correlations, there will be smaller but useful gains over selection cycles in ability to emerge in the field by selection for improved emergence in pots. Direct selection under carefully controlled conditions in the field will produce higher gains, but is more resource consuming than a pot test. We conclude that screening progenies in a pot test in a glasshouse and discarding progenies with poor emergence before a field progeny trial will reduce missing plots due to poor seedling emergence. Selection for improved emergence in pots should lead to an appreciable improvement in seedling emergence in the field over cycles of selection. The pot test is, therefore, a cost effective selection method for the important trait of high seedling emergence.