Inter-relationships among cane yield and commercial cane sugar and their component traits in autumn plant crop of sugarcane

Seventeen diverse clones of sugarcane (Saccharum spp.) (7 early, 6 mid season and 4 late) were planted in October 1991 and 1992 in flooded (FE) and non flooded (NFE) environments for evaluation of cane yield, commercial cane sugar (CCS), internode length, internode number, stalk length, stalk thickness (circumference), stalk number, sugar recovery, and stalk weight. Cane yield showed significant positive phenotypic correlation coefficient (PCC) with stalk number in FE (P ≤ 0.05) and NFE (P ≤ 0.01). Stalk length had a significant positive PCC with stalk weight in both environments, and with internode length in FE (P ≤ 0.05). Commercial cane sugar also expressed significant positive PCC with cane yield in both environments (P ≤ 0.01), but with stalk number only in NFE (P ≤ 0.05). Genotypic correlation coefficients were generally in the same direction as PCC but higher in magnitude. In both environments, stalk number and stalk weight had relatively high positive direct effects on cane yield. However, flooding tended to enhance the direct effect of stalk weight and diminish the direct effect of stalk number on cane yield. Only cane yield and sugar recovery had high direct effects on CCS. Selection for improvement of cane yield can be based on stalk number and stalk weight in both environments. High yielding clones can be further screened for more sugar recovery to improve CCS. This revised version was published online in July 2006 with corrections to the Cover Date.     

Correlation and path coefficients analysis for reproductive traits in Guinea grass

Summary Correlation and path coefficients were calculated for seed yield per plant and its components from 36 clones comprising 8 parental and their 28 single cross clones in Guinea grass (Panicum maximum Jacq.) from data pooled over two years. Seed yield per plant showed significant positive correlation coefficients with branch number per panicle, panicle number per plant, panicle length, branch length, 100 seed weight and day to flower. Path coefficients analysis revealed that panicle number per plant had highest direct effect on seed yield per plant, followed by branch number per panicle, days to flower and 100 seed weight.     

Inter-relationships among total crude protein and digestible dry matter production and their component traits in Guinea grass

Summary Phenotypic and genotypic correlation coefficients of total crude protein per plant (TCP) and digestible dry matter per plant (DDM) with dry matter yield per plant (DMY), tiller number, plant height, stem thickness and leaf-stem ratio, pooled over two years, revealed that TCP and DDM were correlated at both the phenotypic and genotypic levels with DMY, tiller number and plant height. But only DMY had high direct effects on TCP and DDM. Tiller number and plant height had only indirect effects on TCP and DDM via DMY. Thus, selection based on tiller number and plant height may not only improve dry matter yield per plant but also total crude protein per plant and digestible dry matter per plant. Further, screening of high TCP and high DDM clones among the high yielding clones would be a more remunerative approach to improve TCP and DDM in Guinea grass.