Abstract
Predicted decrease in water availability for crop production and uncertainty in climatic conditions require devising the irrigation strategies to increase water use efficiency (WUE) for sustainable crop production. The development of crop cultivars with higher WUE is a pre-requisite for such strategies, particularly in developing countries, including Pakistan, who face stern food security challenges. A two-year field study was conducted following a split-plot randomized complete block design to understand the effects of wheat cultivars (hybrid cultivars, 18A-1 and 18A-2, and local cultivar Ghaneemat IBGE-2016), sowing dates (15th November, 30th November, and 15th December), and irrigation regimes [I (103 mm), II (175 mm), III (254 mm), and IV (330 mm)] at four different growth stages of tillering, booting, anthesis and grain filling on wheat productivity, biomass production and grain yield, and crop-water relations. Early sown hybrid cultivars 18A-1 and 18A-2 showed significantly higher biological and grain yields compared to the local cultivar (59% and 69% higher than the local cultivar). Trends in biomass production and grain yield were also similar at later sowing dates of 30th November and 15th December. However, biological and grain yields decreased with delay in sowing for each cultivar. The data also revealed that hybrid cultivars were better suited to deficient irrigation and generally produced significantly higher biological and grain yields under each moisture regime. Cultivars, sowing dates, and irrigation regime differed significantly for their effects on the Soil Plant Analysis Development (SPAD) values, chlorophyll a and b contents but not for carotenoids. Sowing dates and irrigation regimes had significant effects on relative water content (RWC), water saturation deficit (WSD), water uptake capacity (WUC), and water retention capacity (WRC); however, only WUC varied significantly between the cultivars. The phenological data show that hybrid cultivars took more days to maturity and grain filling than the local cultivar, and days decreased with delayed sowing. The biological and grain yields show significant positive correlations with SPAD values (p < 0.001) and days to maturity (p < 0.001). Our study shows that hybrid wheat cultivars can be opted for higher biomass production and grain yields under deficit irrigation scenarios of semi-arid climatic conditions in Pakistan. Moreover, the hybrid wheat cultivars can perform better than the indigenous cultivar even for delayed sowing dates of 30th November and 15th December.
Highlights
Global climate change is predicted to enhance the frequency and occurrence of dry weather conditions with concomitant adverse effects on cereal production and food security [1,2,3]
The results showed that the highest water saturation deficit (WSD) was found for the hybrid wheat cultivar 18A-2 under irrigation regime II sown on 30th December (Figure 4e)
Cultivation and optimization of hybrid wheat cultivars to obtain higher biomass production and grain yield under less irrigation water are relatively new in the wheatgrowing belt in Pakistan
Summary
Global climate change is predicted to enhance the frequency and occurrence of dry weather conditions with concomitant adverse effects on cereal production and food security [1,2,3]. In the KP province, wheat is grown on more than 52% cultivated area as a rainfed crop with low average yields due to lack of appropriate wheat cultivars suitable for the local climatic conditions and sowing time in winter [29]. Considering the significance of appropriate variety for the rainfed/irrigated regions of Pakistan and in the KP province, selection of the drought-resistant and/or -tolerant wheat cultivars is a pre-requisite for higher crop yields under deficient moisture conditions. Under such scenarios, drought-tolerant or -resistant varieties can survive better [30,31]. The soil at the stitvuedlyy, wsihteereiassathlkeamlienaen acnanlcuaarl eraoiunfsalsliwltays c6l6a.2ymlomaimn thweistthudloywsitetoretagiloonr. gThaensicoilCatand N contents of 8th.2e1stugdkygsi−te1isaanlkdal0in.5e2caglcakrgeo−u1s,sriletyspcleayctliovamelywi(tThalobwleto1t)a.l oTrhgaensicoCilainsdkNncoowntnenttso have low native fofeefrr8tti.il2il1tiytgyuknugdn−e1dratnehdret0ph.5ree2vpgalrkeegnv−c1ea, rloeefsnspecemectiio-vaferlisyde(mcTliamib-laaetri1icd).coTcnhldiemistioaoinltisics. kcnoonwdnittioohnasv.e low native
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