Tuber production in relation to weather parameters and agrometeorological indices prevailing during different phenological stages of Potato crop*

Significant negative correlation of tuber yield with maximum, minimum and mean air temperatures in the stage R₁, (vegetative and tuber initiation phase) and with mean soil temperatures in the stages R₁ and R₁ + R₂ (vegetative phase and tuber development phase) indicated the favourable effect of low soil and air temperatures durtng these stages in contributing towards the higher tuber yield. A high positive correlation between accumulated absorbed photosynthetically active radiation (accu, APAR) in the stages R₁, R₁, + R₂ and R₃ (tuber bulking stage) + R₄ (physiological maturity stage) and tuber yield at physiological maturity was noticed. The fact that tuber yield was positively correlated with thermal regimes i.e. accumulated growing degree days (accu, GOD), accumulated hellothermal unit (accu, HTU) and accumulated soil temperature (accu, ST) indicated the indirect positive contribution of these agrometeorological indices to the tuber yield. The path coefficient analysts revealed three important parameters, viz. min. T in the stage R₁, accu, APAR in the stage (R₁ + R₂) and accum GOD in the stage R₃ which could be used efficiently in predicting the tuber yield.