Harvest index - Sugar yield in sugarcane genetic stocks and its association with yield attributes, nutrients ratio and sucrose

Harvest index in sugarcane based on sugar yield were studied in 30 sugarcane genetic stocks. Statistically significant differences of harvest index - sugar yield among clones, among stages and significant interaction between clone x stage were observed at 0.1% level. The wide variation of harvest index-sugar yield was between 0.061 in Co 62399 to 0.108 in CoC 671 at 10 months. Clones showing high harvest index was observed in CoC 671, B 37172, Co 62174, Co 418, Co 7704, CoA 7601, Co 7508, Co 7204, Co 678, Co 6806, Co 7717, and Co 997 and low harvest index was observed in Co 62399, CP 44-101, Co 1148, Co 617, CoJ 64, Co 62101, NCo 310, H 50-7209, Co 775, Co 419 and Co 975. Harvest index was increased from 0.081 at 10 months to 0.086 at 12 months. Harvest index-sugar yield had significant positive correlations with leaf N/S, N/Cl, N/Na, cations/anions, sheath N/S ratio, sheath cations minus anions, sucrose % juice and sugar yield - 8, 10 and 12 months, internodes numbers, cane volume, cane height, cane thickeness, cane wegith, harvest index - sugar yield at 10 and 12 months. There were significant negative correlations of harvest index-sugar yield with sheath N/P and N/Si ratios. Harvest index-sugar yield at 10 and 12 months had no associations with leaf N/K, N/P, N/Ca, N/Mg ratios, cations minus anions, sheath N/K, N/Ca, N/Mg, N/Cl, N/Na ratios and culm basic density.