Investigation of sugarcane genetic stocks for leaf blade nitrogen-magnesium ratio at grand growth period and its associations with nutrients ratios, yield components, sucrose and yield of cane and sugar

Abstract

At grand growth period, thirty sugarcane genetic stocks were studied for leaf blade N/Mg raio. Differences of leaf N/Mg ratio among clones, among stages and interaction between clone x stage were significant statistically at 0.1 % level. According to clone mean, the lowest and the highest leaf N/Mg ratio were 7.00 in Co 62399 and 11.43 in CoC 671. The wide range of leaf N/Mg ratio was in between 5.50 in Co 62399 at 4 months to 15.14 in Co 775 at 7 months. Clones CoC 671, Co 7712, Co 775, Co 7304, NCo 310, CoA 7601, Co 6806, Co 997, POJ 2878, and Co 7717 had recorded high leaf N/Mg ratio, while low leaf N/Mg ratio was observed in Co 62399, CP 44-101, Co 678, Co 7704, H 50-7209, Co 419, Co 62175, Co 6304, Co 1148 and Co 740. with the advancement of the age of the crop, leaf N/Mg ratio increased from 7.47 at 4 months to 11.49 at 7 months. The significant positive associations of leaf nitrogen-magnesium ratio were observed with leaf N/P, N/K, N/Ca, N/S, N/Cl, N/Na, N/Si, cations/anions ratio, sheath N/K, N/Ca, N/S ratios, sucrose% juice-8, -10, -12 months, harvest index-sucrose % juice and harvest index-C.C.S. %. There was a significant negative association between leaf N/Mg ratio and harvest index-cane yield. But leaf N/Mg ratio had no association with leaf cations minus anions, cane and sugar yield, stalk numbers, cane volume, cane density, cane height, cane thickness, cane weight, culm basic density and harvest index-sugar yield.