No abstract

The shortage of green fodder for farm animal during summer has been increased in Egypt. Therefore, great efforts must be directed towards the improvement of summer forage crops. Sorghum could be provided as a solvent to this problem, since it is considered the most important forage crop during summer. This investigation is a contribution to improvement the sorghum fodder yield by selection.Selected 17 strains from F2 segregation generation of the superior hybrid between forage sorghum variety (Quna) and dwarf male -sterile line (Red land) were evaluated to study the genetic variability for fodder yield and its component. Also, genetic variability was determined for all studied traits.The results showed that there are highly significant differences for all studied traits in the three cuts in two seasons and for combined analysis. The estimate of heritability in broad sense were high for all studied traits in the three cuts also. The genetic advance had considerable values in the three cuts with respect to all studied traits. In addition, there are three promising strains (No 5, 6 and 9) for total forage yield. Also these strains had a high In situ dry matter disappearance (ISDMD) and In situ organic matter disappearance (ISOMD). The DM percentages of the three strains were higher than parent (1). The OM and CP % of strains 5 and 6 were higher than parent (1). The feed intake by bucks from strains 5 and 6 were significantly (P<0.05) higher than strain 9 and parent (1). No significant differences among parent (1) and other strains in digestion coefficients were recorded of all nutrients except CP digestibility of strains 5 and 6 which was significantly (P<0.05) higher than strain 9 and parent (1). The DM yields were 5.23, 6.68, 5.57 and 4.50 ton/ fed. for parent (1), strains 5, 6 and 9, respectively. The TDN yields were 3.503, 4.586, 3.798 and 2.959 ton/ fed. for parent (1), strains 5, 6 and 9, respectively. The DCP yield was 0.389, 0.591, 0.472 and 0.317 ton/fed for parent (1), strains 5, 6 and 9, respectively. Therefore, genetically improved sorghum strains can be obtained and subsequently, these strains could be directly cultivated or hybridized to produce superior F1 hybrids.