Yield of Wheat in the United Kingdom: Recent Advances and Prospects

From 1948 to the present, wheat (Triticum aestivum L.) yields in the UK have increased by an average of 110 kg ha−1 each year. This rate of increase has been at least maintained in recent years. The greater yields have been associated with the adoption of cultivars of shorter stature, which are resistant to lodging and reach anthesis ≈1 wk earlier than old cultivars. In the last two decades, most of these cultivars have carried the rht D1b dwarfing gene. The full yield benefits from modern cultivars have depended on high rates of N fertilization and the use of herbicides and effective fungicides. Data from recent trials with candidate cultivars and F1 hybrids suggest that further genetic gain in yield will be achieved during the next decade. Improved crop protection through chemicals may also enable farmers to obtain greater yields. In the longer term, substantial genetic gain in yield may be achieved if breeders are able to produce cultivars with faster growth rates and greater biomass at maturity. One way to achieve this would be to modify the photosynthetic enzyme rubisco so that its oxygenase activity is reduced. However, cultivars with potentially faster growth rates would require even more N fertilizer if their greater yield potential is to be realized. [1]


The effect of soil strength on the yield of wheat

Although it is well-known that high soil strength is a constraint to root and shoot growth, it is not clear to what extent soil strength is the main physical stress that limits crop growth and yield. This is partly because it is difficult to separate the effects of soil drying and high soil strength, which tend to occur together. The aim of this paper is to test the hypothesis that for two different soil types, yield is closely related to soil strength irrespective of difference in soil water status and soil structure. Winter (Triticum aestivum L., cv. Hereward) and spring wheat (cv. Paragon) were grown in the field on two soils, which had very different physical characteristics. One was loamy sand and the other sandy clay loam; compaction and loosening treatments were applied in a fully factorial design to both. Crop growth and yield, carbon isotope discrimination, soil strength, water status, soil structure and hydraulic properties were measured. The results showed that irrespective of differences in soil type, structure and water status, soil strength gave a good prediction of crop yield. Comparison with previous data led to the conclusion that, irrespective of whether it was due to drying or compaction (poor soil management), soil strength appeared to be an important stress that limits crop productivity. [2]


Markers associated with a QTL for grain yield in wheat under drought

Drought is a major abiotic stress that adversely affects wheat production in many regions of the world. The objective of this study was to identify quantitative trait loci (QTL) controlling grain yield and yield components under reduced moisture. A cross between common wheat cultivars ‘Dharwar Dry’ (drought tolerant) and ‘Sitta’ was the source of one hundred twenty-seven recombinant inbred lines evaluated for two-seasons in a field under differing soil moisture regimes in Ciudad Obregon, Sonora, Mexico. An SSR/EST-STS marker map was constructed and a grain yield QTL on the proximal region of chromosome 4AL was found to have a significant impact on performance under reduced moisture. This region was associated with QTL for grain yield, grain fill rate, spike density, grains m−2, biomass production, biomass production rate, and drought susceptibility index (DSI). Molecular markers associated with these traits explained 20, 33, 15, 23, 30, 26, and 41% of phenotypic variation, respectively on chromosome 4A. Microsatellite locus Xwmc89 was associated with all significant QTL covering a 7.7 centiMorgans (cM) region and generally explained the greatest proportion of phenotypic variation. The alleles associated with enhanced performance under drought stress were contributed by Dharwar Dry. Microsatellite marker wmc89 may be useful for marker assisted selection to enhance drought tolerance. [3]


Response of Bread Wheat to Sowing Dates and the Genotypes in Morocco

A field study was conducted to determine the effects of sowing date on the growth and yield of different bread wheat genotypes in two locations of Morocco (the plain of Saïs; Douyet and the Atlas Montaigne; Annoceur). The trial was conducted using a randomized complete block design with three replications in 2011/2012 and 2012/2013. The chosen dates were: 1st and 15th November in Douyet; 1st and 15th December in Annoceur and three bread wheat varieties (Achtar, Mehdia and Arrehane). Results revealed that seedlings in 1st November in the Saïs region and 1st December in the Atlas Montaigne increased grain yield for 11.15% compared to seasonal sowing, and any delay in bread wheat sowing might reduce wheat yield. The variety Arrehane surpassed the two other varieties Mehdia and Achtar in both growing seasons and at both locations with an average of 10.95% and 21.05% for grain yield, and for all components measured; number of spike m-2, 1000-grain weight, number of grains per spike, plant height and harvest index. [4]


Effects of Foliar Application of Boron (B) on the Grain Set and Yield of Wheat (Triticum aestivum L.)

Aims: The objective of this study was to evaluate the effect of foliar application of boron (B) on the grain set and yield of wheat (cv. Shatabdi).

Study Design: The experiment was designed with six boron treatments, arranged in a randomized complete block design (RCBD) with three replications.

Place and Duration of Study: The field trial was conducted at Bangladesh Agricultural University (BAU) farm, Mymensingh during 27 November 2010 to 24 March 2011.

Methodology: The B treatments were (i) B control, (ii) soil application of B, (iii) seed priming into boric acid solution, (iv) foliar spray of B at primordial stage of crop, (v) foliar spray of B at booting stage and (vi) foliar spray of B at primordial and booting stages. The rate of B for soil application was 1.5 kg B ha-1 from boric acid (17% B) and the rate for each foliar spray was 0.4% boric acid solution. Seed priming was done by soaking wheat seeds into 0.1% boric acid solution for 10 hours and then seeds were dried before sowing. Every plot received 115 kg N, 25 kg P, 75 kg K and 15 kg S per hectare from urea, TSP, MoP and gypsum, respectively.

Results: The treatment receiving foliar spray of B at both primordial and booting stages of the crop performed the highest yield (3630 kg ha-1) which was statistically similar with the yield recorded with foliar spray of B at booting or primordial stage of crop and with soil application of B before crop (wheat) was sown; all the yields were significantly higher over the yield noted with seed priming or control treatment. The control treatment (no B application) had the lowest grain yield (2600 kg ha-1) which was significantly lower than the yield observed with the seed priming treatment.

Conclusion: Wheat yield was affected due to grain set failure induced by boron deficiency and it was possible to overcome this element deficiency by soil application at 1.5 kg B ha-1 or foliar application of 0.4% boric acid solution at primordial or booting stage of crop.[5]


Reference

[1] Austin, R.B., 1999. Yield of wheat in the United Kingdom: recent advances and prospects. Crop Science, 39(6), pp.1604-1610.

[2] Whalley, W.R., Watts, C.W., Gregory, A.S., Mooney, S.J., Clark, L.J. and Whitmore, A.P., 2008. The effect of soil strength on the yield of wheat. Plant and Soil, 306(1), pp.237-247.

[3] Kirigwi, F.M., Van Ginkel, M.A.R.T.I.N., Brown-Guedira, G., Gill, B.S., Paulsen, G.M. and Fritz, A.K., 2007. Markers associated with a QTL for grain yield in wheat under drought. Molecular Breeding, 20(4), pp.401-413.

[4] Bendidi, A., Daoui, K., Kajji, A., Bouichou, L., Bella, M.B., Ibriz, M. and Dahan, R., 2016. Response of bread wheat to sowing dates and the genotypes in morocco. Journal of Experimental Agriculture International, pp.1-8.

[5] Fakir, O.A., Rahman, M.A. and Jahiruddin, M., 2016. Effects of foliar application of boron (B) on the grain set and yield of wheat (Triticum aestivum L.). Journal of Experimental Agriculture International, pp.1-8.