Management of weather variability and terminal heat stress in wheat by altering sowing time

Abstract

Wheat can be grown in a wide range of climatic conditions but many biotic and abiotic factors limit
its yield. The present investigation was carried out to manage weather variability and terminal heat
stress in wheat by altering sowing time. A field experiment was conducted at the Research Farm,
School of Climate Change and Agricultural Meteorology, Punjab Agricultural University, Ludhiana
during rabi 2013-14 with wheat variety PBW 621 sown on three i.e. D1 (29th October), D2 (12th
November) and D3 (28th November). In the earlier sown crop, the maximum and minimum
temperature was higher during initial and lower during later crop growth stages and the reverse
pattern was observed with delay in sowing. As relative humidity is inversely proportional to
temperature, thus relative humidity increased during initial crop growth stages and decreased at
later stages of crop growth with delay in sowing. The crop received a total of 157.2, 143.6 and 171.6
mm rainfall under D1, D2 and D3, respectively. Periodic number of tillers, plant height and dry
matter were significantly higher under earlier sown crop and decreased with delay in sowing.
Yield attributing characters i.e. number of effective tillers, ear length, number of spikelets per ear,
grain weight per ear and 1000 grain weight were higher under D1 followed by D2 and D3. The
highest grain yield was produced in D1 (46.2 q ha–1) which was statistically at par with D2 (45.3 q
ha–1) and was significantly higher than D3 (38.9 q ha–1). The study highlights the role of earlier
sowing of wheat in managing the weather variability impact and thermal heat stress under Punjab
conditions.