Impact of nitrogen fertilization on yield and quality for plant cane, ratoon crop and correlation analyses of some sugarcane varieties

Abstract

This study was conducted in 2018/2019 plant cane and first ratoon 2019/2020 in El-Mattana Research Station, (latitude of 25.18^o N and  longitude of 32.06^oE), Luxor Governorate, Egypt to investigate the effect of nitrogen levels and nitrogen application number on yield and  its components of some new sugar cane varieties. The field experiment included twenty-seven treatments that represented  combinations of three application numbers [two, three, and four times], three nitrogen fertilization levels [180, 210, and 240 kg N/fed=  4200 m2], and three sugar cane varieties [G4, G.3, and G.T.54-9]. We used a split-split plot design with three replications. The number of  applications (doses), nitrogen fertilization levels, and sugarcane varieties tested all showed significant differences in all traits studied.  Millable canes/m2, millable cane height, weight, cane yield/fed, and sugar yield/fed all increased significantly when nitrogen levels were  increased from 180 to 240 kg N/fed. In plant cane only, the G.4 outperformed the other two varieties in millable cane height, diameter,  weight, cane yield/fed., sugar yield/fed., and purity percentage. However, in terms of millable cane number in plant cane and first ratoon,  the commercial variety G.T.54-9 outperformed the other two varieties. While G3 had the highest sucrose and sugar recovery  percent in plant cane and first ratoon, brix percent and pol percentage were only in plant cane, but sugar recovery and purity percentage  were only in first ratoon. In both seasons, planting the variety G.4 fertilized with 240 kg N/fed split into four doses resulted in the highest  cane and sugar yields/fed. Data were collected on cane yield and its components, sugar yield and sugar quality traits. ANOVA correlation  analysis was done. Analysis of variance revealed that cane yield had perfectly positive correlation (r = 1.0) and highly significant  correlation (P < 0.01) with sugar yield. On the other hand sugar yield had very high positive correlation with sugar quality traits. The  results illustrated that there are significant correlation coefficient (P ≤ 0.05) between each of cane yield and sugar yield with sugar  recovery % was observed. Cane yield was more closely correlated with millable cane length followed by millable cane diameter and  millable weight. This has important implications for selection of varieties to be used as parental material for crossing purposes. The  present study in general found that there are negative correlation between agronomic characters and juice quality parameters. With  regard to the biochemical characters in the present study, sucrose percent was closely correlated with sugar recover, pol%, brix% and  purity%. This indicated that selection through pol%, brix% and purity% would produce varieties with high levels of sucrose recovery  percent.