热研15号刚果臂形草的选育与利用

1991年从哥伦比亚国际热带农业研究中心(CIAT)引入6095刚果臂形草(Brachiaria ruziziensis G.et E.CIAT6095),1992-1993年在网室和田间进行生态适应性观测,1994-1996年进行品种比较试验,1999-2004年进行区域试验,1999-2005年在海南、云南和福建进行生产试验。结果表明:热研15号刚果臂形草产草量达209865.83 kg/hm²·a,极显著(P<0.01)高于热研6号珊状臂形草(B.brizantha cv.Reyan 6)54.43%,高于热研3号俯仰臂形草(B.decumbens cv.Reyan 3)43.76%;热研15号刚果臂形草喜湿润热带气候,适宜在海拔1000~2000 m,年降水1000 mm以上的热带、亚热带地区生长,具有良好的耐旱能力,在pH4.5~5.0和极端贫瘠的土壤具有良好的持久性和丰产性;适于建植高产、优质、耐久的放牧型草地;固土护坡能力强,适于作水土保持的先锋草种。     

Forage Yield and Sucrose Response of Rhodes and Ruzi Grass to Cutting Height and Cutting Frequency Under Irrigation

The development of irrigated pastures in the Sudan is still at its infancy. The present study determined the influence of 2 cutting heights (2.5 and 5.0 cm) and 4 cutting frequencies (4-, 6-, 8-, and 10-week) on forage yield as dry matter and forage sucrose of Rhodes grass ( Chloris gayana Kunth. cv. Massaba ) and Ruzi grass ( Brachiaria ruziziensis Germain et Everard cv. Congo Signal ) under irrigated conditions. Forage yield interactions involving species X cutting height X cutting frequency were significant. These yield interactions were attributed to differences in growth period and growth rhythm of the two species. On average, Rhodes exhibited a short growth period (13 months) compared to Ruzi grass (20 months). Forage yield and forage sucrose were, on average, superior in Ruzi compared to Rhodes grass. Forage yield and forage sucrose averaged 5.2 t ha⁻¹ and 7.2 % fw sucrose in Ruzi compared to 2.8 t ha⁻¹ and 6.9 % fw sucrose in Rhodes grass. Forage yield and forage sucrose of both species were negatively correlated with cutting frequency. The highest forage yield may be obtained at an 8-week cutting frequency in Rhodes (45.6 t ha⁻¹ yr⁻¹) compared to a 10-week cutting frequency in Ruzi grass (88 t ha⁻¹ yr⁻¹). Results suggest that very high forage yields as dry matter and forage sucrose of Rhodes and Ruzi grass may be possible under irrigated conditions in the Sudan at a cutting frequency of between 8 to 10 weeks.     

NaCl胁迫对刚果臂形草种子萌发及幼苗生理效应的研究

研究了NaCl胁迫对刚果臂形草种子的萌发及幼苗的生理效应,结果表明:低浓度盐处理有利于促进种子萌发,对幼苗的生长也未表现出不利影响,但叶片中脯氨酸含量成倍增加;随着盐胁迫浓度的增大,刚果臂形草种子发芽率、发芽指数、活力指数及幼苗的生长高度、鲜重、干重均降低,质膜透性增加,形态和生理上都表现出盐害效应;叶片中脯氨酸和叶绿素含量增加,是刚果臂形草自身为抵御外界不良盐滞环境所做出的适应性生理效应。     

臂形草属牧草品种比较试验

对８种臂形草属热带牧草的品种进行了比较试验研究，３年的试验结果表明，饲草产量以网脉臂形草产量最高，年干物质产量为２４２７１ｋｇ／ｈｍ＾２，其次为ＣＩＡＴ ６０９５刚果臂形草，年干物质产量为２０９８６ｋｇ／ｈｍ＾２，四生臂形草产量最低，年干物质产量仅为１１８２ｋｇ／ｈｍ＾２。     

Pachytene Chromosomes of Brachiaria ruziziensis Germain et Evrard

Brachiaria ruziziensis is a sexual diploid tropical grass species of wide adaptation and good forage quality. Pachytene chromosomes were studied in morphological detail and all nine chromosomes were identified by their length, centromere position, and size and distribution of chromomeres. The idiogram prepared for the first time in this species consists of four median and five submedian chromosomes.