Genetic Variance and Performance of Five Sugarcane Varieties for Physiological, Yield and Quality Traits Influenced by Various Harvest Age

Field experiments was carried out at Shandaweel Agricultural Research Station, Sohag Governorate during 2017/2018 and 2018/2019 seasons. The aim of this research to investigate three harvest dates at ages of(11,12 and 13 months)on the performance of five promising sugarcane varieties G.84-47,G.2003-47, G.2003-49,G.2004-27 and the commercial variety G.T.54-9 as a control. The harvest age up to 13 months recorded the highest values of cane and sugar yields in plant cane (52.08 and 5.95 tons/fed (fed=0.42ha), respectively) and first ratoon crops (55.16 and 6.70tons/fed, respectively).Varieties showed significantly differed in stalk length, stalks number, as well as brix, sucrose, sugar recovery percentages, cane and sugar yields (ton/fed.).The best performance was reported by the following varieties (G2004-27, G2003-47 and GT54-9) under all harvest ages, Also, these varieties registered the best cane yield (52.01,52.35 and 53.94 tons/fed, respectively) and sugar yields (5.48,6.09 and 6.03ton/fed,respectively).Results indicated significantly increasing physiological characters such as, leaf area index (LAI), crop growth rate (CGR),and net assimilation rate (NAR) with increasing harvest age as well as, these traits varied significantly between varieties. There is a positive and significant correlation between CGR, NAR and cane yield, which should be used to predict cane yield. Broad-sense heritability for cane and sugar yields and their traits varied from the lowest trait registered by stalk length(34.23%)to the highest value(95.82%)recorded by sucrose percentage. It could be more effective if selected higher heritability for yield than the lower. Varietal differences in growth and maturity rates should be taken into account when making harvesting decisions.