Resumen

DAI, Zhongmin et al. Grain position in spike of wheat (Triticum aestivum L.) affects glutenin macropolymer particles distribution. Agrociencia [online]. 2014, vol.48, n.3, pp.295-306. ISSN 2521-9766.

Glutenin macfopolymef (GMP), an important component of wheat (Triticum aestivum L.), consists of high weight (HMW-GS) and low-molecular-weight (LMW-GS) gutenin subunits. In wheat, the subunit composition and GMP characteristics are important factors affecting processing quality. The objective of this study was to characterize the effects of soil water status, cultivar and grain position in wheat spike, on GMP particles distribution. Wheat cultivars Jinan 17, Yannong 24 and Lumai 21 with different end-use quality were used in 2009-2011 growing season, and two water regimes (irrigated and rainfed): two irrigations (750 m³ ha^-1 each at jointing and booting stage) for irrigated, and none for rainfed. The experimental design was a complete randomized block with three replicates; data were analyzed whith ANOVA and Tukey test (p ≤ 0.05) for treatment means, using SPSS. All determinations were replicated three times. Plot dimension was 3 mx3 m. At maturity, the heads flowering on the same date were sampled and detached as basal and distal grains according to the position on spikelets. GMP particles distribution and HMW-GS content were affected (p ≤ 0.05) by soil water, genotype and grain position. Basal grains on middle spikelets showed higher (p ≤ 0.05) HMW-GS and GMP content than those in distal grains at maturity. The volume and surface area percentage of >100 µm GMP particles in basal grains were higher (p ≤ 0.05) than that in distal grains, but those of <12 µm particles in basal grains were lower than that in distal grains. Compared with irrigation, percent volume and surface area of >100 µm GMP particles in basal and distal grains were significantly increased (p ≤ 0.05), and content of HMW-GS and GMP were also increased in rainfed condition. As a result, basal and distal grains have different quality characteristics and application. A promising breeding strategy would be to improve grain yield and quality by increasing average grain weight rather than grain number within a spikelet. When managing for wheat production, the water factor was the most important manipulation to regulate the yield and quality.

Palabras llave : High-molecular-weight glutenin subunit; glutenin macropolymer; grain position; rainfed cultivation; wheat.

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