A STUDY OF THERMAL CHANGES ON PHYSIOLOGY AND PADDY YIELD OF FINE RICE CULTIVARS UNDER SUBTROPICAL CONDITIONS
Tasneem Khaliq1, Amjed Ali 1, 2, Ashfaq Ahmad1, Muhammad Ahmad3,
Azhar Mahmood4 and Muhammad Mubeen1
1Agro-climatology Lab., University of Agriculture, Faisalabad, Pakistan 2University College of Agriculture, University of Sargodha, Sargodha, Pakistan, 3Agriculture Adaptive Research Complex, Dera Ghazi Khan, Pakistan, 4Adaptive Research Farm, Sheikhupura, Pakistan
ABSTRACT
A thematic research was planned to find out the effects of thermal changes on crop physiology and paddy yield of fine rice under subtropical conditions. Various parameters related to crop physiology and yield were recorded in order to establish the causes underlying the variations in paddy yield associated with transplanting date and cultivar. Throughout the growth period of different rice cultivars, early transplanting (1st of July) significantly enhanced LAI over subsequent late transplanting (15th and 30th of July). LAI of different cultivars was also significant. Maximum LAI values were found at 75 DAT in all the treatments. LAD was positively correlated with paddy yield. Percent increase in NAR (g m-2 d-1) in case of 30th July was 14.3, followed by 15th July 10.97 as compared to 1st July. While in case of varieties, NAR (g m-2 d-1) was not significantly affected by different varieties. Paddy yield also decreased in the subsequent transplanting dates from 4.71 t ha-1 to 4.22 t ha-1and 4.01 t ha-1 in 1st, 15th and 30th July, respectively. Paddy yield of different cultivars was also significantly different and it was highest in case of cv. Basmati-515 as compared to other cultivars. Increase in temperature decreased paddy yield.
