Genetic and Phenotypic Path Analyses and Heritability in Sugarcane1
- M. S. Kang,
- J. D. Miller and
- P. Y. P. Tai2
This study was undertaken to determine phenotypic and genetic correlation coefficients among several agronomic traits in sugarcane (Saccharum spp.) and to analyze their interrelationships through path-coefficient analyses. Other objectives were to determine broad-sense heritability and genetic advance under selection for the traits studied. Random selections from two biparental crosses (‘CP 59-50’ ✕ ‘CP 57-603’ and ‘CP 62-374’ ✕ ‘CP 57-614’) were evaluated in the field for several attributes in plant cane, and first- and second-ratoon crops. Genetic path-coefficient analyses indicated plant height to be less important than stalk diameter and stalk number as a component of cane yield; but at the phenotypic level, all three components were of equal importance. Sucrose (%) had a large direct positive effect on sugar per ton of cane (S/T) whereas Brix (percent soluble solids) had a small negative direct influence on S/T. The S/T component exerted a greater direct effect on tons per hectare of sugar (THS) than did tons per hectare of cane (THC). Broad-sense heritability estimates based plot means for various traits ranged from a low of 77% for THS to a high of 94% for stalk diameter. Expected genetic advance for various traits was reasonably high under selection intensities of 2 to 30%. THC estimated from the weight of a 10-stalk sample per plot was genetically and phenotypically correlated with THC determined by weighing the entire plot (rs = 0.92, rp = 0.64) which suggested that a 10-stalk sample per plot would be adequate to determine THC.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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