نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجوی دکتری، گروه زراعت و اصلاح نباتات، دانشکدگان کشاورزی و منابع طبیعی، دانشگاه تهران، کرج، ایران.
2 استاد، گروه زراعت و اصلاح نباتات، دانشکدگان کشاورزی و منابع طبیعی، دانشگاه تهران، کرج، ایران
3 استادیار، بخش تحقیقات ذرت و گیاهان علوفه‌ای، مؤسسه تحقیقات اصلاح و تهیه نهال و بذر، سازمان تحقیقات، آموزش و ترویج کشاورزی، کرج، ایران.
4 دانشیار، گروه زراعت و اصلاح نباتات، دانشکدگان کشاورزی و منابع طبیعی، دانشگاه تهران، کرج، ایران.
چکیده
کلیدواژه‌ها
عنوان مقاله [English]
نویسندگان [English]
To investigate the effect of different levels of water deficit and foliar application of some drought stress mitigators on phenological characteristics, yield components and yield of two grain maize hybrids a field experiment was conducted as strip-plot factorial arrangements in randomized complete block design with three replications at the research field of the Seed and Plant Improvement Institute, Karaj, Iran in 2024 and 2025. The vertical factor consisted of three irrigation regimes (full irrigation, moderate stress and severe stress, supplying 100, 75 and 50% of crop water requirement) and the horizontal factor comprised the combination of four foliar treatments (control, L-arginine, salicylic acid and glycine betaine) and two grain maize hybrids, TWC.647 and SC.704. Under moderate and severe stress, grain yield decreased by 19.1% and 43.9%, respectively. Drought stress increased anthesis-silking interval, shortened grain filling period duration, reduced kernels ear-1, and decreased thousand kernel weight. The highest grain yield under full irrigation (7.26 t ha-1) obtained from SC.704 with application of glycine betaine, whereas under moderate and severe stress conditions the highest grain yield (6.01 and 4.17 t ha-1, respectively) obtained from TWC.647with application of the same treatment. Overall, the grain yield response to foliar application depended on both stress level and hybrid. Glycine betaine was superior under all conditions and its effect was more pronounced as stress intensified, however the superior maize hybrid changed with increasing stress level. Therefore, selection suitable maize hybrid for different stress levels together with application of glycine betaine is an appropriate management strategy for grain maize production under limited water conditions in Karaj and similar semi-arid regions.
Keywords: Maize, irrigation regime, drought tolerance, glycine betaine, grain filling period duration.
Introduction
Maize (Zea mays L.) is sensitive to water deficit around flowering stage, when kernel set and grain yield are most vulnerable (Sah et al., 2020). Drought commonly delays silk emergence more than pollen shedding, thereby widening the anthesis–silking interval and restricting kernel formation (Fuad-Hassan et al., 2008). Foliar application of stress-mitigator compounds can play a potential role in reducing drought stress adverse effects.
Glycine betaine acts as a compatible osmolyte that contributes to osmotic adjustment and protection of the photosynthetic apparatus, whereas salicylic acid participates in stress signaling and antioxidant defense and L-arginine is a precursor of nitric oxide and polyamines (Chen and Murata, 2011). However, direct field comparisons of L-arginine, salicylic acid and glycine betaine across different water-deficit levels and maize hybrids remain limited.
Therefore, this study aimed to evaluate the effects of these compounds on phenological traits, grain yield and yield components of two maize hybrids under three irrigation regimes.
Materials and Methods
A two-year field experiment was carried out in 2024 and 2025 growing seasons at the research field of the Seed and Plant Improvement Institute, Karaj, Iran (35°47′54″N, 50°56′10″E, 1279 m a.s.l.). The experiment was conducted as strip-plot factorial arrangements in randomized complete block design with three replications.
Three irrigation regimes supplying 100, 75 and 50% of crop water requirement were assigned to vertical plots. The factorial combinations of four foliar treatments (control, L-arginine, salicylic acid and glycine betaine) and two grain maize hybrids (TWC.647 and SC.704) were assigned to horizontal plots. Spraying was applied three times at ten-day intervals from the six- to eight-leaf to flowering stages.
Phenological stages were recorded when 50% of plants reached each stage. Phenological traits, ears per square meter, kernel no. ear-1, kernel no. row, thousand-kernel weight and grain yield, adjusted to 14% moisture, were measured. Homogeneity of error variances was examined using Bartlett’s test before combined analysis of variance, and means were compared using the Tukey test at the 5% probability level.
Results and Discussion
Water deficit delayed reproductive development, but the magnitude of delay depended on foliar treatment. Under severe stress conditions, glycine betaine reduced days to tasseling, anthesis and silking from 64.2, 68.3 and 78.3 days in the control to 60.7, 64.4 and 72.2 days, respectively. It also reduced the anthesis–silking interval from 9.9 to 7.8 days and increased grain filling period duration from 24.3 to 27.1 days. These responses agree with the greater drought sensitivity of silk expansion than male flowering reported by Fuad-Hassan et al. (2008).
All foliar treatments partially alleviated grain yield loss, although the magnitude of their effect depended on irrigation regime and maize hybrid. Under full irrigation conditions, the highest grain yield was obtained from glycine betaine-treated SC.704 (7.26 t ha-1), whereas under moderate and severe stress conditions, the highest grain yield obtained from glycine betaine-treated TWC.647 (6.01 and 4.17 t ha-1, respectively).
Glycine betaine also increased kernels no. ear-1 and thousand-kernel weight under water deficit conditions. The superior performance of glycine betaine may be associated with its established roles in osmotic adjustment and protection of membranes and the photosynthetic machinery (Chen and Murata, 2011), which can help maintaining assimilate supply to developing kernels and is consistent with the improved growth and yield of drought-stressed maize reported by Shafiq et al. (2021).
Overall, application of glycine betaine before flowering stage, combined with a suitable hybrid adapted to the expected stress level, are recommended for grain maize production under limited water conditions in Karaj and similar semi-arid regions.
References
Chen, T.H.H. and Murata, N. 2011. Glycinebetaine protects plants against abiotic stress: Mechanisms and biotechnological applications. Plant, Cell and Environment, 34(1), pp.1–20. DOI: 10.1111/j.1365-3040.2010.02232.x
Fuad-Hassan, A., Tardieu, F. and Turc, O. 2008. Drought-induced changes in anthesis–silking interval are related to silk expansion: a spatio-temporal growth analysis in maize plants subjected to soil water deficit. Plant, Cell and Environment, 31(9), pp.1349–1360. DOI: 10.1111/j.1365-3040.2008.01839.x
Sah, R.P., Chakraborty, M., Prasad, K., Pandit, M., Tudu, V.K., Chakravarty, M.K., Narayan, S.C., Rana, M. and Moharana, D. 2020. Impact of water deficit stress in maize: phenology and yield components. Scientific Reports, 10, e2944. DOI: 10.1038/s41598-020-59689-7
Shafiq, S., Akram, N.A., Ashraf, M., García-Caparrós, P., Ali, O.M. and Abdel-Latef, A.A.H. 2021. Influence of glycine betaine (natural and synthetic) on growth, metabolism and yield production of drought-stressed maize (Zea mays L.) plants. Plants, 10(11), e2540. DOI: 10.3390/plants10112540
کلیدواژه‌ها [English]
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