Morpho-physiological characters associated with genotype and environment interactions in sugarcane (Saccharum officinarum L.)

Results of the study revealed that the AMMI (additive main effect and multiplicative interaction) statistical analysis identified four major morpho-psychological characters associated with sugarcane yield: number of leaves, stalk weight, stalk diameter, and millable stalks, which explained 97%, 95%, 89%, and 91% of the genotype-environment interaction (G x E) by the first and second bilinear components, respectively. The characters that showed positive correlation to sugar yield were location-specific. In Tarlac [Philippines], stalk weight and number of millable stalks were correlated with tonnage yield (r=0.67 and 0.69, respectively) and sugar yield (r=0.61 and 0.55, respectively). Stalk weight and number of millable stalks were important components of sugar yield (Lkg/ha), with r=0.58 and 0.70, respectively, and tonnage yield (TC/ha), with r=0.55 and 0.85, respectively in Balayan. Significant correlations were obtained on stalk length (r=0.49), millable stalk (r=0.91) and stalk weight (r=0.78) to tonnage yield (TC/ha) in La Carlota. Similarly, stalk diameter (r=0.40), millable stalks (r=0.81), and stalk weight (r=0.43) were correlated to sugar yield (Lkg/ha). In Victorias, internode length, number of millable stalks and stalk weight contributed much to sugar yield (r=0.48, 0.77, and 0.48, respectively); number of millable stalks and stalk weight to tonnage yield (r=0.91 and r=0.68, respectively). VMC 90-239 was correlated with tonnage (R square=0.85) VMC 86-550 with sugar yield (R square=0.98). The positive correlations of sugar yield (Lkg/ha) and tonnage yield (TC/ha) to these morpho-physiological characters associated with G x E suggests the potential for selection for specific sites. Generally, varieties that were more adapted to sunny climate and lesser rainfall [i.e., Balayan (2,907 mm) and Tarlac (2,211 mm)] had semi-erect to droopy leaves while varieties that were more adopted to cloudly climate and high rainfall [i.e., La Carlota (3,833 mm) and Victorias (3,579 mm)] had erect to semi-erect leaf characteristics. This indicated genotypic response to environmental conditions. The AMMI biplot data analysis was useful in displaying the genotypes specifically adopted to a particular environment. Thus, VMC86-550, VMC71-39, and VMC90-239 were specifically adapted to Tarlac and Victorias; VMC76-529, PHIL74-64, VMC84-524 and PHIL80-13 in Balayan; and VMC87-599, VMC84-524, and PHIL80-13 in La Carlota. When compared to location means, a yield advantage ranging from 14-27% was obtained for genotypes specifically adapted to a particular environment