The effect of drought stress and planting date on morphophysiological traits and yield in Two varieties of millet

Drought stress is one of the important challenges of agricultural crop production in the arid and desert region. In order to increase yield, indrouction of drought resistance cultivars, and reduction water consumption, this experiment was conducted to recognize effects of drought stress and planting date on morphophysiological and yield of two varieteds of millet.

Materials and Methods :

The experiments were carried out as a split plots arranged in randomized complete block design with three replications in Zahak Agricultural Research Station in 2015 and 2016. The main factor included planting dates (1, 15 and 30 March and 15 April) and drought stress (50, 65 and 80% of field capacity) were in sub sub plots. Grain yield and traits of plant height, plant height, 1000 seeds weight, dry forage yield, chlorophyll, proline, day to maturity, and day to flowering were determined.

Results :

The results showed that maximum and minmun grain yield was obtained at 50 and 80 percent of filed capacity with average of 1679 and 469 kg hg-1, respectively. Grain yield, day to flowering number, day to maturing number, chlorophyle concentration, dry forage yield, 1000 seed weight, and plant height was affected by cultivars. Maximum grain yields was in Bastan cultivar (1200 kg ha-1). Grain yield, day to flowering number, day to maturing number, chlorophyle concentration, dry forage yield, 1000 seed weight, and plant height was infulunced by interaction effects of planting date, drought stress, and cultivar. Maxium grain yield (2711 kg hg-1), day to maturing (72.2 days), cholorphyle concentration (6.50 mg g-1), dry forage yield (9475.6 kg ha-1), 1000 seed weight (4.55 g ), and planting height (122.5 cm) were for Bastan culrivar in 15 March and 50 percent irrigarion.

According to the obtained results of forage and grain yield, it seems that planting at 15th March play a key role in increasing yield of millet, because of water and temperature suffiencny. The plant at this date had more contribution to transfer the produced phytotsenythetic materials to seeds. Howerver, delay in planting date resulted in late season heat stress at seed filling time and abnormality in photosynthesis to transpiration ratio which it can dercrease the transfer of photosynthetic materials to seeds. It seems that sowing of cultivar of Bastan in comparison with conventional one has resulted in highest resistant to drought stress. We can recommend as resistant cultivar of millet at 15th of March palnting date and 50 percent of field capacity For the Sistan region the relationship between farmers and extension specialists, and researcher can increase yield in drought years. Although Millet is resistant to drought, increasing the soil moisture to 80 percent of field capacity resulted in reducing chlorophyll and yield components. Sowing tin 15 March because of availability of moisture and proper temperature, has significant role in increasing yield. The millet in this date was able to transfer its photosynthetic products to grains; however, delay in sowing as result of hot weather the relative of photosynthesis to transpiration in grain filling period.