YIELD, GROWING DEGREE DAYS, PHENO THERMAL INDEX AND HEAT USE EFFICENCE OF WHEAT (TRITICUM AESTIVUM) AS INFLUENCED BY SOWING DATES

Foto KASHTA, Nikollaq BARDHI, Moltina PREBIBA, Alirami SALIJI, Hazir POLLOZHANI

Abstract

The study aimed to predict: 1. the different stages of wheat development, depending on planting time and the GDD accumulated. 2. To calculate the phenothermal index (PTI) for different stages of development 3. To calculate the heat use efficiency (HUE) for grain yield. A trial was set up using a randomized complete block with three replications in the Botanical Garden of the Agricultural University of Tirana. Three sowing dates (Nov.11, Nov. 26, and Dec 11) and one wheat cultivar (Dajti), were tested. The results showed the plant cycle and GDD required from planting to ripening is reduced in late sowing dates. The values of PTI in the early stages of development, from germination till tillering, decreased, while from the tillering till flowering, these values increased for all three planting dates. The highest heat use efficiency for grain yield (2.82 kg/ha/0C day) was recorded under normal sowing i.e. 11th November sown crop. Subsequent delay in sowing resulted in a decrease in HUE. November 26 and December 11 sowing time, had values of 2.49 and 1.89 kg/ha/0C day, respectively. The yield was significantly affected by planting dates. The maximum grain yield (6430 kg/ ha) was recorded when planting was done on November 11th, which decreased gradually and significantly to 4130 kg/ ha when planting was done on Dec.11. The yield attributes studied in this experiment showed a smaller decrease i.e. 22.4 % in grains/spike and 8.0% in 1000-grain weight as compared with the 35.8% decrease in the grain yield when sowing was delayed till Dec.11th as compared with Nov.11th.

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