Abstract: Sorghum bicolor Sorghum sudanense cv. Mengnong Qingsi No.2, a forage crop cultivar selected from interspecies hybrid of sorghum male sterile line A₄ and white hull sudangrass, had been bred through 9 successive generations by choosing 4 times the good single plant in the F₂ hybrid population and one time mixed choice, and by comparative tests of varieties, and yield experiments at various plots of land. The roots of the forage crop developed well, the growing period was around 134 days, and the plant height reached 350 cm in general, with mature green stems and leaves, strong tillers, and full regeneration vigour. Each year,it could be cut 3 times during the growing season, and the fresh yield and seed yield averaged 132000 kg/hm² and 5600 kg/hm² respectively. The stems and leaves were tender and juicy, with a stem-to-leaf weight ratio of 3.01. The content of crude protein in the dry matter amounts to 11.7% at the jointing stage. During the flowering stage, the content of crude protein reaches 9.32%, crude fat 3.48%, crude fiber 37.57%, crude ash 5.68%, nitrogen-free extract 42.12%, the ratio of sugar content 3.89%, and is rich with 17 amino acids. with low content of cyanogen, Mengnong Qingsi No.2 boasts high nutrition value, is palatable, and can be used as fresh forage, for ensiling and making hay. Moreover, the plant is strong in resistance ability and ecological adaptability, and is suitable to be cultivated in areas where the effective accumulated temperature equals or is higher than 2400℃.

Key words: Grassland science, A4 male sterility line of sorghum, White hull sudangrass, Wide cross breeding, Sorghum bicolor Sorghum sudanense cv. Mengnong Qingsi No.2, Feeding value

摘要： 从高粱雄不育系A4×白壳苏丹草杂种F2代分离群体中开始选择优秀单株,通过4次单株选择、1次混合选择及品比、区域与和生产试验,历经9个世代育成蒙农青饲2号高丹草。该品种根系发达,株高350cm,生育期134d,绿杆成熟,分蘖多,再生性强,每年刈割利用3次,鲜草产量132000kg/hm²,种子产量5600kg/hm²;茎叶柔嫩、多汁,茎叶比3.01,拔节期粗蛋白质含量11.70%,开花期的粗蛋白质含量9.32%、粗脂肪3.48%、粗纤维37.57%、粗灰分5.68%、无氮浸出物42.12%,糖锤度3.89%,富含17种氨基酸,CN-含量低,营养价值高,适口性好,可青饲、青贮或晒制干草;植株抗逆能力强,生态适应性广,适宜在有效积温≥2400℃的地区推广种植。

关键词: 草原学, 高粱雄不育系A4, 白壳苏丹草, 远缘杂交育种, 蒙农青饲2号, 饲用价值