Breeding Of Sorghum-Sudangrass 'Mengnong No.4 And No.5'

Sorghum and Sudangrass are annual of often cross pollinated crops.Their morphology and biological characteristics are quite different, and they had themselves' advantages and defects. In order to breed new forage crop variety of good characters combining Sorghum with Sudan grass, three interspecific hybrids F1 were obtained via crossing between male-sterile line Sorghum 11A and black hull Sudan grass, white hull Sudan grass, brown hull Sudan grass respectively. Then new lines were obtained via selecting and breeding. This paper was focused on observing agronomic characters of Mengnong No.4 and Mengnong No.5 selected from Sorghum 11A×black hull sudangrass and Sorghum 11A×brown hull sudangrass respectively, and was identified with isozyme, AFLP and ISSR. The main results were as follows:1. The average growth periods of Mengnong No.4 and Mengnong No.5 were 135days to 124 days respectively, the plant heights were 401.3cm and 370.9cm respectively, the tillering number per plant were 7.4 and 7.2 respectively, the ratio of stems to leaves were 2.77 and 2.88 respectively, the ratio of sugar content were 6.75% and 6.46% respectively, the cyanide content were 18.89mg/kg and 16.70mg/kg respectively, the average fresh yields were 9968.94kg/667m2 and 9400.93kg/667m2 respectively, which were increased by 17.97% and 12.26% respectively in comparison with the control. And seed yields of Mengnong No.4 and Mengnong No.5 were 377.36kg/667m2 and 397.83kg/667m2 respectively, which were increased by 6.36% and 12.18% respectively in comparison with the control.2. The crude protein contents of Mengnong No.4 and Mengnong No.5 were 14.89% and 14.15% respectively, the total amino acids contents were 10.625% and 9.500% respectively, the lysine contents were 0.641% and 0.550% respectively. They have strong adaptability, and grew well at Tongliao, Hohhot and Ulanchabu in Inner Mongolia.3. There were significant differences in characteristics of POD isozymes in the leaves at the tillering stage and in young ears at booting stage among varieties (or lines). The proxidase isozyme zynograms phenotype can be used as an important basis of identifying Sorghum—Sudangrass varieties (lines) in protein level.4. There were 3986 AFLP loci in total, and 3546 were polymorphic loci among them. The percentage of polymorphism was 88.96%. At the level of 0.74 (genetic distance), the 8 materials can be divided into 3 groups. The first group included Mengnong Qingsi No.1, Mengnong Qingsi No.2, Mengnong No.3, Mengnong No.5 (11A—black hull Sudangrass), Late Maturing 11A—black hull Sudangrass and 11A—white hull Sudangrass. The second group included Everlush. The third groupe included Mengnong No.4 (11A—brown hull Sudangrass).5. DNAs of 11 Sorghum—Sudangrass varieties (or lines) were amplified with 12 ISSR primers. There were 888 ISSR loci in total, and 591 were polymorphic loci among them. The percentage of polymorphism was 66.55%. At the level of 0.68 (genetic distance), the 11 materials can be divided into 3 groups. The first group included Mengnong Qingsi No.1, Mengnong No.5 (11A—black hull Sudangrass), Mengnong Qingsi No.2, brown hull Sudangrass, Mengnong No.3, black hull Sudangrass and Late Maturing 11A—black hull Sudangrass.The second group included Mengnong No.4(11A—brown hull Sudangrass)and white hull Sudangrass. The third group included 11A—white hull Sudangrass and female sterile lines 11A.