AN EXPERIMENT field was conducted at El- Mattana ........Agricultural Research Station, Luxor Governorate, to evaluate the yield and ratooning ability of 30 sugarcane genotypes (clones) along with the check cultivar G.T 54/9 during three different crop cycles; plant cane (PC), first ratoon (FR), and second ratoon (SR) crops during 2011/2013 harvesting seasons. A randomized complete block design with three replicates was used. Results indicated that the evaluated genotypes varied significantly (P = 0.05) within and among crop cycles for stalk length, stalk diameter, stalk density, stalk weight, stalks number, cane yield, Brix, sucrose content, purity, sugar recovery and sugar yield. The evaluated genotypes differed significantly in their ratooning ability (RA) for all studied traits. Over evaluated genotypes, means of stalk diameter, stalk weight, stalk density and cane yield in plant cane were higher than those in the first and second ratoon crops, while means of Brix, sucrose, purity and sugar recovery percentages in the second ratoon were higher than those in plant cane and first ratoon crops.
The relative influence of genotypic variance (d2g) in determining the phenotypic variance was primary to genotype by crop interaction variance (d2gc) and error variance (d2e) for all studied traits. Broad sense heritability (H%) estimates were high for cane yield and its components as well as sugar yieldsince it ranged from 82.53% for cane yield to 95.06% for stalk length. High genotypic coefficient of variation (GCV%) estimates was for stalk weight ( 27.01%), stalk density (39.36 %) and stalk number (32.57 %), while low estimates were for stalk length and juice quality traits (2.05% ≤ GCV% ≥ 7.99%). Genotypic variance (d2g) was primary to error variance (d2e) for RA of cane yield and its components as well as sugar yield and juice quality traits. The highest heritability estimates of RA were for stalk weight (98.10 %), stalk density (98.24%), stalk number (99.46%) and sugar yield (96.73%) with high estimates of genotypic coefficient of variation (GCV) for the same traits (22.78%, 32.26%, 36.41% and 27.26%, respectively).