The impact of high temperature stress, normally encountered during grain development phases in wheat under late sown conditions, was studied by measuring grain growth rate (mg day−1 grain−1), grain yield (g plant−1) in relation to ADP glucose pyrophosphorylase (AGPase) activity (nmol mg−1 min−1), a key regulatory enzyme in starch biosynthesis. The experimental material comprised nine genetically diverse homozygous genotypes of spring wheat and their six F1s. These were grown in randomised block design with three replications at CCS Haryana Agricultural University, Hisar, India on two dates of sowing 26th November, 2007 (timely, E1) and 24th December, 2007 (late, E2). The rate of grain growth was greatly reduced as temperature increased in late sown environment. Grain growth rate among the parental genotypes was highest in UP 2425 and cross PBW 343 × PBW 435 in both the environments. Mean ADP glucose pyrophosphorylase (AGPase) activity was maximum at 14 days after anthesis in timely sown while in late sown the activity was maximum at 21 days after anthesis in PBW 435, EIGN 1 and EIGN 8 and crosses EIGN 8 × UP 2425, EIGN 1 × Raj 3765 and PBW 343 × PBW 435. A significant positive association in both timely and late sown environments was evident between grain yield and grain growth rate, while in late sown environment, strong positive and significant correlation was observed between grain yield and grain growth rate and also between grain growth rate and AGPase activity in crosses PBW 343 ×WH 283, PBW 343 × WH 542 and PBW 343 × PBW 435. This suggested that increase in grain growth rate and AGPase activities resulted in increase in grain yield and have considerable impact on the yield performance of wheat.
Authors:A. Khan, H.H. Liu, A. Ahmad, L. Xiang, W. Ali, A. Khan, M. Kamran, S. Ahmad and J.C. Li
Higher plant population and nitrogen management is an adopted approach for improving crop productivity from limited land resources. Moreover, higher plant density and nitrogen regimes may increase the risk of stalk lodging, which is a consequence of complex interplant competition of individual organs. Here, we aimed to investigate the dynamic change in morphology, chemical compositions and lignin promoting enzymes of the second basal inter-nodes altering lodging risk controlled by planting density and nitrogen levels. A field trial was conducted at the Mengcheng research station (33°9′44″N, 116°32′56″E), Huaibei plain, Anhui province, China. A randomized complete block design was adopted, in which four plant densities, i.e., 180, 240, 300, and 360 × 104 ha−1 and four N levels, i.e., 0, 180, 240, and 300 kg ha−1 were studied. The two popular wheat varieties AnNong0711 and YanNong19 were cultivated. Results revealed that the culm lodging resistance (CLRI) index of the second basal internodes was positively and significantly correlated with light interception, lignin and cellulose content. The lignin and cellulose contents were significantly and positive correlated to light interception. The increased planting density and nitrogen levels declined the lignin and its related enzymes activities. The variety AnNong0711 showed more resistive response to lodging compared to YanNong19. Overall our study found that increased planting densities and nitrogen regimes resulted in poor physical strength and enzymatic activity which enhanced lodging risk in wheat varieties. The current study demonstrated that stem bending strength of the basal internode was significantly positive correlated to grains per spike. The thousand grain weight and grain yield had a positive and significant relationship with stem bending strength of the basal internode. The results suggested that the variety YanNong19 produces higher grain yield (9298 kg ha−1) at density 240 × 104 plants ha−1, and 180 kg ha−1 nitrogen, while AnNong0711 produced higher grain yield (10178.86 kg ha−1) at density 240 × 104 plants ha−1 and with 240 kg ha−1 nitrogen. Moreover, this combination of nitrogen and planting density enhanced the grain yield with better lodging resistance.
A field experiment was conducted at the Eastern Block, Department of Central Farm, Tamil Nadu Agricultural University, Coimbatore, India, on medium black soils during the North Eastern Monsoon Season (October-January) of 2002. The experiment was laid out in a randomized block design (RBD) with varying combinations of organic and inorganic sources along with a control and the recommended dose of fertilizers. The results revealed that the number of tillers per plant was enhanced by the application of a combination of organic and inorganic sources. The leaf area index (LAI) increased up to 60 days after sowing and thereafter declined. Leaf area duration (LAD) and crop growth rate (CGR) were reduced at maturity. Treatments receiving 50% N from yeast sludge composted coir pith (YCCP) with ZnSO
and 50% inorganic N gave a significantly higher number of tillers, LAI and CGR compared to the control. The dry matter accumulation differed in all the stages, but higher values were recorded in this same treatment. Thus, due to the higher number of tillers, higher LAI, CGR and greater dry matter accumulation, treatment with 50% N from YCCP with ZnSO
and 50% inorganic N (T
) produced the highest grain yield (2185 kg ha
), which was on par with 50% N from pleurotus composted coir pith (PCCP) with ZnSO
and 50% inorganic N (2103 kg ha
grainyield and yield components of bread wheat in the Bale highlands of southeastern Ethiopia. pp. 316-324. In: The Eleventh Regional Wheat Workshop for Eastern, Central and Southern Africa . CIMMYT, Addis Ababa, Ethiopia