Evaluation on Forage Quality and Biomass Energy Characters of Inbred Vegetative Lines of Napier Grass
|School||Nanjing Agricultural College|
|Keywords||Elephant grass Botanical characters Clone Forage Quality Calorific value Cluster analysis|
Napier grass N51 (Pennisetum purpureum cv. N51) is a highly heterozygous line, which was introduced in 1985 by researchers to Academy of Agriculture Sciences of Jiang Su province. Researchers got the line heading and inbreding through the method of shading and obtained more than one hundred plant lines with different botanic traits. These traits can be inherited steadily through the method of vegetative propagation. These lines are not only precious germplasm resources, but also can be directly used as forge after selecting. This experiment is carried out to cluster these lines according to their botanic traits and dry matter yield,then analyze and compare their qualities used as forage,and at the same time,the heat value of different lines were determined and the correlation between heat value and botanic traits were conducted. Below are the results:1 Using the plant height, dry matter yield and tillering number of different lines as parameters for clustering analysis, all lines were clustered into 11 groups, but there are still big differences between sub-groups. These sub-groups were categorized further into 14 groups according to the plant height as categorizing parameter and dry matter yield, tillering number as attributing parameters.2 The correlation between dry matter yield and botanic traits is carried out and the resut shows that the correlation between dry matter yield and botanic traits are significant(P<0.01),the correlation between dry matter yield and plant height,leaf length,leaf width are positive,the correlation between dry matter yield and tillering and stem diameter is not significant. Among lines of similar plant height,the correlation between dry matter yield and tillering is significant (P<0.01)and positive.3 The highest DM yield of Napier grass is obtained by cutting after a whole growth period. The highest DM yield can not be obtained by increasing the cutting frequencies, but the forage quality can be enhanced.4 The comprehensive evaluation on forage quality were carried out according to in vitro dry matter digestibility (IVDMD),crude protein(CP), acid detergent fiber(ADF),neutral detergent fiber(NDF) and digestible dry matter yield. The results show that among all 14 groups, there are 3 groups whose scores are over 2.7, including 2 high stalk group,1 medium stalk group; there are 9 groups whose scores are between 2.5-2.7,including 3 high stalk groups,4 medium stalk groups,2 dwarf groups; there are 2 groups whose scores are under 2.5, including 1 high stalk group,1 dwarf group. Among all groups, the group high stalk,medium tillering and high yield has the best forage quality; the group high stalk,less tillering and high yield has the worse forage quality.5 The result of heat value and correlation between heat value and botanic traits show that the heat value of high stalk and medium stalk groups is higher than dwarf groups. The difference between high stalk and medium stalk is small. For all lines, the correlation between heat value and plant height, leaf width, leaf length is positive (P<0.01), and stalk diameter and tillering is not significant. But these significance is not coherent among groups. In high stalk group, the correlation between heat value and botanic characters are not significant; in medium stalk group, the correlation between heat value and plant height is positively significant, it is negatively significant between heat value and stem diameter; in dwarf group,the correlation between heat value and leaf length is significant. Factor analysis shows that plant height, leaf length and DM yield are the main element of factors which influence the heat value of lines of napier grass.