In an effort to characterise and select promising sweet stem sorghum genotypes with enhanced biofuel productivity, the present study investigated phenotypic variability present among diverse sweet stem sorghum genotypes based on ethanol production and related agronomic traits. One hundred and ninety genotypes were evaluated. Data were subjected to variance, cluster, correlation, path coefficient and principal component analyses. Significant differences (P?<?0.01) were detected among tested genotypes for all measured traits. Days to flowering varied from 62 to 152 with a mean of 93. Plant height varied from 90 to 420?cm with a mean of 236?cm. Stem diameter ranged from 7 to 31?mm with a mean of 16?mm. Biomass yield varied from 6.668 to 111.2?t?ha?1 with a mean of 30?t?ha?1. Stalk dry matter content ranged from 17.2% to 44.2% with a mean of 29.8%, while fibre content varied from 8.92% to 34.8% with a mean of 17.2%. The stalk brix yield varied from 3.3% to 18.9% with a mean of 12.1%. Ethanol productivity ranged from 240.9 to 5500?l?ha?1 with a mean of 1886?l?ha?1. The best ethanol producing genotypes were AS203, AS391, AS205, AS251 and AS448. Days to flowering, plant height, stalk brix and stem diameter exerted the greatest indirect effects on ethanol production through higher biomass production. Biomass yield had the greatest direct effect on ethanol production. Therefore, the above traits should be considered during breeding sorghum for bio-ethanol production. Also, the traits had high heritability values, hence selection should provide for good genetic gains. Overall, the above sweet stem sorghum genotypes are useful genetic resources for breeding of sorghum with enhanced bio-ethanol production. 相似文献
Empirical research has shown that the use of manure significantly improves crop yield, soil fertility and water and moisture conservation. Despite these documented benefits, however, there is a concern on the downward trend of manure use in agriculture in China. This paper examines factors contributing to this downward trend, with a particular focus on human excreta used in agriculture. Empirical analysis based on data from stratified random sampling of rural households in five provinces of China shows that about 85% of human excreta was still used as manure in agriculture in 2007 which was less than a decade ago when nearly all human excreta was used as manure. Econometric results suggest that income growth, rising population density and improvement in rural transportation significantly contribute to declining use of human excreta as manure in agriculture. These results imply that the current downward trend will continue given China's rising economic growth, urbanization and rural infrastructural improvement. 相似文献
This study compared five commercially available probiotics vis-à-vis antibiotic growth promotant (AGP) supplementation and absence of feed additive based on efficiency, intestinal morphometry, and energy digestibility in improving broiler chicken production. A total of 630 straight run (Cobb) day-old broiler chicks were distributed to seven treatments following a completely randomized design, with ten replicates per treatment and nine birds per replicate per cage. Dietary treatments consisted of basal diet in combination with the following: without probiotics and AGP supplementation (treatment 1); 75 ppm each of chlorotetracycline (CTC) and Zn bacitracin (treatment 2); probiotic A, Bacillus subtilis (treatment 3); probiotic B, Bacillus subtilis (treatment 4); probiotic C, Enterococcus faecium (treatment 5); and probiotic D, Bacillus subtilis (treatment 6); probiotic E, Enterococcus faecium, Bifidobacterium spp., Pediococcus spp., and Lactobacillus spp. (treatment 7). At day 42, energy digestibility was determined by fasting three randomly selected birds from each treatment for 12 h and then subjecting them to their corresponding dietary treatments. Excreta were collected and pooled after 24 h of feeding. Pooled excreta were weighed, oven-dried, and subjected to energy analyses after 3-day collection. Apparent total tract metabolizable energy was then computed. At day 47, three birds were randomly selected per treatment for intestinal morphometry (villi height and crypt depth) of the duodenum, jejunum, and ileum. Dietary supplementation using probiotics showed no significant effect on overall body weight, weight gain, feed consumption, feed efficiency, dressing percentage, mortality, harvest recovery, carcass quality parameters (e.g., meat to bone ratio and abdominal fat content), intestinal morphometry, and energy digestibility. Birds under treatment 7 (basal feed + probiotic E) generated the highest income over feed and chick cost.
An effective male sterility system enables targeted crosses between parent plants with desired and complementary characteristics. The use of chemical hybridising agents (CHAs) to induce male sterility is quicker and more efficient than manual emasculation. This study investigated the concentration, stage of application and frequency of application of ethyl 4'fluorooxanilate (E4FO) for inducing male sterility of sweet stem sorghum without affecting female fertility. In Trial 1, the dose rate of E4FO was determined to optimise male sterility. In this experiment three genotypes were tested at E4FO dose rates. In Trial 2 the frequency of application of E4FO was determined using three sweet stem sorghum genotypes, three E4FO doses, and six frequencies of application. Data on sterility was inferred based on seed set and seed count from the treated plants. Male sterility was achieved when E4FO was applied during heading stage using the following rates: 1?g l?1, 1.5?g l?1 and 2?g l?1, with more than one application. Applying E4FO twice during the heading stage at a rate of 2?g l?1 would induce male sterility in the tested sweet stem sorghum genotypes, a result that could be useful in hybrid breeding programmes. 相似文献