AGROCLIMATIC POTENTIAL OF SUNFLOWER IN PA RAIBA STATE, BRAZIL .1. TEMPERATURE AND SOLAR-RADIATION

The objective of this research was to analyse temperature and solar ra diation in determining the best date of planting for sunflower in Para iba State, Brazil. Two or three sites of each of the 12 homogeneous mi cro-regions (HMR) of the State were selected. Data of monthly mean tem perature and mean solar radiation, and temperature index (TI) for sunf lower were used to establish the growth index GI (product of phototerm al quotient and TI). The GI and the relative ground cover were used to determine the accumulated crop growth index (AGI). Months with maximu m AGI were considered as the most suitable planting dates for sunflowe r on the selected sites of the 12 HMR of Paraiba State, in the absence of water deficit. It was found that, for irrigated conditions, the be st planting time for sunflower in Paraiba State would be from July to August for most of HMRs.