QTL Analysis for Traits Associated with Feeding Value of Straw in Rice (Oryza sativa L.)

Genetic improvement of the digestibility of rice straw for increasing the utilization of the whole rice plant as feedstuffs is an important way to solve the feedstuffs shortage in southeastern China. To elucidate the genetic basis of the traits affecting the digestibility of rice straw, a rice population of 111 recombinant inbred lines （RILs） derived from a cross of Nekken 2xGaya was used to map the quantitative traits loci （QTLs） for in vitro dry matter digestion （IVDMD）, the percentages of nonstructural carbohydrate （NSC） and acid detergent fiber （exclusive of residual ash, ADFom） in 2005 and 2006. IVDMD was positively correlated with NSC, and negatively correlated with ADFom. A total of 16 QTLs were detected in the two years, and the amounts of variation explained by individual QTLs ranged from 6.9% to 15.5%. Some QTLs for IVDMD and ADFom on chromosome 2 were detected in the two years. On chromosome 2, the interval RM475-RM3515 contained QTLs for IVDMD in the two years and for NSC in 2006 only, while the interval RM3874-RM5305 influenced ADFom in the two years and NSC in 2005 only. At those loci, Gaya contributed favorable alleles to IVDMD and NSC, while Nekken 2 contributed positive alleles to ADFom.

Impacts of Different Stages of Nitrogen Dressing on Feeding Value of Forage Summer Maize

A trial of investigating impacts of nitrogen dressing at different stage on feeding value and physiological characteristics of forage summer maize (Ludan50) has been conducted by means of potted planting. The results suggested that biomass yield, grains yield and feeding value of all treatments were significantly raised compared CK without nitrogen dressing. Nitrogen dressing at the jointing stage for one time could raise the dry matter yield in terms of biomass, thus improving feeding value. Separating total dose of dressing nitro-

Nutritional Evaluation and Palatability of Major Range Forbs from South Darfur, Sudan

The nutritive value of rangelands in Southern Darfur, Sudan could be improved by introduction and multiplication of nutritious forbs with the objective of increasing livestock production in the area. The present study was conducted to evaluate the nutritive value and palatability of eleven range forbs collected at flowering stage from Gahzal Gawazat, Southern Darfur, Sudan using chemical analysis. The crude protein (CP) ranged from 6.8% in Oxygonum atriplicifolium with lowest digestible crude protein (DCP) 2.8% to 16.4% in Zornia diphylla with highest DCP 11.73%. The highest and the lowest crude fiber (CF) values were obtained in Commelina spp (56.4%) and Sesamum alatum (25.9%), respectively. NDF and DMI values were maximum and minimum for Zornia diphylla (44.9 and 2.67%) and Alysicarpus glumaceus (35.3 and 3.4%), respectively. The total digestible nutrients (TDN) ranged from 57.1% in Blepharis linariifolia to 69.3% in Tribulus terrestris with highest digestible energy (DE) in later while the lowest DE was obtained in Commelina spp (2.4%). The calculated in vitro organic matter digestibility (IVOMD) was highest for the Canavalia ensiformis (50.27%) and lowest value (43.17%) for Commelina spp. Zornia diphylla, Tribulus terrestris and Sesamum alatum showed highest nutritive value, while Alysicarpus glumaceus, Oldenlandia senegalensis and Chrozophora brocchiana showed highest palatability. It is concluded that these rangeland forbs are palatable and their CP and energy contents are sufficient to support different classes of livestock in South Darfur, Sudan.