Exploitation of phenotypic, genotypic and quality related variations in Sudan pearl millet collection for the development of forage suited varieties

Pearl millet (Pennisetum americanum L) is an important grain and forage crop in many countries. In Sudan, even though an indigenous crop (over 1600 accessions of the crop have been collected from Sudan and stored in the Genetic Resources Unit (GRU) of the Agricultural Research Corporation (ARC) at Wad Medani), pearl millet is exclusively grown for grain production. This study therefore, aimed at the exploitation of inter- and intra ¬seasonal, phenotypic, genotypic and quality variations among the Sudan's pearl millet collections for possible development of forage type varieties. In this regard, 200 accessions were obtained from GRU of the ARC and were grown at a nursery in 2006 at the Gezira Research Station Farm (GRSF) to screen for glabrously leaved accessions at the flowering stage. Consequently, 100 accessions with glabrous leaves were selected for further study. The strategy of the study thereafter, comprised three levels. The first was to verify the existence of inter- and intra- seasonal, phenotypic, genotypic and quality variabilities among the 100 selected accessions. The second was to pin point the high forage yielding accessions in each season. The third was to determine the common high yielding accessions in the three or any two consecutive seasons. The study of the phenotypic variation involved three field trials arranged in an augmented design grown in autumn and winter (2008/2009) at the GRSF and in summer (2008) at the Gezira University Experimental Farm (GUEF). The quality variability involved the proximate analysis viz crude protein (CP), crude fibre (CF), nitrogen free extract (NFE), dry matter (DM), organic matter (OM) and ash of 42, 38 and 37 accessions selected based on their high dry matter yields from those grown in autumn, winter and summer, respectively. The analysis was done at Elobeid Research Station. The genotypic (molecular) diversity analysis involved 36 accessions (33 from Darfor and 3 from Kordofan) selected based on morphological clustering of the accessions from the field trials. Simple sequence repeat (SSR) markers were used and the analysis was done at the Biotechnology and Biosaftely Research Center of the Agricultural Research Corporation (ARC) at Shambat, Sudan. Wide and highly significant differences in the total fresh and dry forage yield, days to harvest, plant height, number of tillers/plant and leaf/stem ratio were found among the accessions. The dry forage yield ranged from 0.19 to 12.08 t/ha in autumn, from 0.14 to 13.68 t/ha in winter and from 0.02 to 19.31 t/ha in summer. Based on the overall means, the highest dry forage yield was obtained during autumn and winter seasons (6.1 and 6.0 t/ha respectively). Based on their morphological characters, the 100 accessions of pearl millet during autumn, winter and summer seasons were grouped into four main clusters. Wide diversity among pearl millet accessions was therefore, evident from such clustering. Significant intra- and inter- seasonal variations were also evident in all parameters of proximate quality analysis among the studied pearl millet accessions. The crude protein (CP) ranged from 3.7 to 10.8 % in summer; from 3.7 to 13.8 % in autumn and from 3.1 to 18.6 % in winter seasons. The overall means indicated that, highest crude protein was obtained during autumn (7.1%) and winter (7.3%) seasons compared to 5.9% in summer