نوع مقاله : مقاله پژوهشی
نویسندگان
1 استادیار ، بخش تحقیقات علوم زراعی و باغی، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان فارس، سازمان تحقیقات، آموزش و ترویج کشاورزی، شیراز، ایران.
2 دانشیار، بخش تحقیقات علوم زراعی و باغی، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان فارس، سازمان تحقیقات، آموزش و ترویج کشاورزی، شیراز، ایران.
چکیده
کلیدواژه‌ها
عنوان مقاله [English]
نویسندگان [English]
This study aimed to investigate the effect of sowing date and enviromental factors during different growth stages on some phenological characterisitcs and grain yield of commercial bread wheat cultivars. The experiment was carried out as split-plot arrangements in randomized complete block design with three replications at the Darab reaesrch field station in 2018-19 and 2019-20 cropping cycles. Five sowing dates: October 27, 11, and November 26, December 11, and 26, were assigned to the main plots. Five commercial wheat cultivars: Mehregan, Barat, Khalil, Sarang, and Setareh, were randomized in the subplots. Results showed that the late maturity cultivars, Khalil and Brat, had higher grain yield in earlier sowing dates. Early maturity cultivars, Setareh and Mehregan, had less yield reduction in later sowing dates. The highest and lowest mean grain yield obtained from November 11 (6934 Kg ha-1) and December 26 (5775 kg ha-1), respectively. Number of days and required growing degree-days (GDD) decreased with delaying sowing date. The decrease of required GDD to reach commencement of stem elongation, anthesis and maturity stages from the first to fifth sowing date was 181, 282 and 528 GDD, respectively. Simultaneous effect of weather variables and sowing date on some characteristics revealed that the first two components explained approximately 41% of total variation. Results showed that temperature was the most important factor controlling the phenological stages duration. Despite the importance of temperature, changes in sowing date can alter the required GDD for phenological stages due to other environmental factors. In general, the results of this study can provide an insight into bread wheat cultivars responses to different climatic conditions and development of new bread wheat cultivars adapted to target environments.
Keywords: Bread wheat, growing degree-days, stem elongation, anthesis, physiological maturity.
Introduction
Global warming due to climate change is significant challenge for the sustainability of wheat production due to the complex interactions between genotype and climate factors (Nuttall et al., 2018). Under conditions of climate change, it is important to evaluate the response of plant phenological stages to climate change. Therefore, accurate understanding of genotype × environment interactions (GEI) and selecting superior genotypes adapted to environments and climate fluctuations requires thorough knowledge of genetic adaptation principles and their physiological and environmental bases (Ashworth et al., 2023). In this context, it is crucial to investigate the effect of environmental factors such as meteorological data on wheat phenological stages and grain yield as well as their interaction effects during vegetative and reproductive growth. Partial least squares regression (PLSR) analysis of environmental parameters can elucidate changes in crop yield resulting from genotypic responses in different environments and identify the most sensitive growth stages to environmental and climatic variables (Porker et al., 2020). The main objective of this study was to investigate the impact of agroclimatic indices and meteorological factors on different phenological stages and grain yields of commercial bread wheat cultivars in different dates for bread wheat breeding programs for development of new cultivars with wide adaptability to chamging climate in target environments.
Materials and methods
Five commercial bread wheat cultivars, Mehregan, Barat, Khalil, Sarang, and Setareh, as sub-plots were planted in five sowing dates, October 27, November 11, November 26, December 11, and December 26 as main plots using split-plot arrangement in randomized complet block design with three replications at the Darab resrach field station in 2018-2019 and 2019-2020 cropping cycles. For each sowing date, the number of days and required growing degree-days (GDD) from emergence to commencement of stem elongation (CSE), anthesis (Anth) and physiological maturity (PMA), and grain filling duration (GFD) from anthesis stage were calculated for all bread wheat cultivars. Analysis of variance was performed using SAS ver. 9.1 software, and Tukey's test was used for mean comparisons. To investigate the simultaneous effect of meteorological covariables and sowing date on bread wheat cultivars, the partial least squares regression (PLSR) method was used in GEA-R v4.1 software (Pacheco et al., 2015). The Y matrix consists of grain yield variables measured on five cultivars in five sowing dates, and the X matrix contains meteorological covariables including mean minimum temperature, mean maximum temperature, number of sunny hours per day and total rainfall, whcich were calculated for the four phenological stages in each sowing date. Finally, the PLSR results were displayed graphically using biplot with the coordinates of environments, genotypes, and meteorological covariables simultaneously based on the first two components.
Results and Discussion
Combine analysis of variance showed that the difference in the number of days to CSE stage among the studied bread wheat cultivars in the five different sowing dates was not significant. However, the required GDD for this stage decreased by 181 degree-days from the first sowing date (October 27) to the fifth sowing date (December 26). The longest number of days to Anth and PMA for the cultivars corresponded to the first sowing date. Additionally, the highest and lowest required GDD for the Anth and PMA stages belonged to the first and last sowing dates, respectively. Cv. Khalil had the most and Setareh had the least number of days and total required GDD to reach different phenological stages. Generally, the temperature requirement of early breadwheat cultivars was lower than late cultivars (Jalal Kamali and Sharifi, 2010). Delaying the sowing date exposed the cultivars to higher mean daily temperatures and reduces the length of the phenological periods, thereby decreasing the number of days needed for anthesis and physiological maturity (Ashena et al., 2015). The number of days and required GDD for GFD both decreased from the first sowing date to the last. While the number of days required for the GFD stage did not differ significantly among bread wheat cultivars, the required GDD for this stage was lower in early-maturing bread wheat cultivars.
The highest average grain yield of 6935 kg ha-1 obtained from the second sowing date (November 11), while the lowest grain yield of 5775 kg ha-1 belonged to the last sowing date (December 26). The highest and lowest averages grain yield belonged to cv. Khalil (6639 kg ha-1) and Setareh (5557 kg ha-1), respectively. Relatively late cv. Khalil and cv. Barat performed well in early sowing dates. While, the early cv. Setareh and cv. Mehregan showed less variation in grain yield in latest sowing date when compared with the earliest.
Study of the simultaneous effects of meteorological covariates and sowing date on grain yield using PLSR showed that mean minimum and maximum temperatures during Anth and GFD stages had a substantial impact on grain yield for delayed sowing dates. Early cv. Setareh and cv. Mehregan were more tolerant to higher temperatures during Anth and GFD stages. The higher grain yield in the second sowing date could be due to greater total rainfall as well as lower temperatures during Anth and GFD. Overall, temperature strongly controlled the duration of different phenological stages. Despite the importance of temperature, changes in sowing date also altered the required GDD for the duration of phenological stages of bread wheat due to other climatic and environmental factors. In conclusion, the results of this study can provide an insight into bread wheat cultivars responses to different climatic conditions and development of new bread wheat cultivars adapted to target environments.
Reference
Ashena, M., Kafi, M., Jafarnejad, A. and Sharifi, H.R. 2015. Evaluation of planting date and nitrogen effects on the development stages of wheat cultivars and their relationship with yield and yield components in Nishabur. Crop Production, 8(4), pp.143-162. (in Persian). DOI: 20.1001.1.2008739.1394.8.4.8.4
Ashworth, A.J., Allen, F.L. and Saxton, A.M. 2023. Using partial least squares and regression to interpret temperature and precipitation effects on maize and soybean genetic variance expression. Agronomy, 13(11), pp. 2752. DOI:10.3390/agronomy13112752
Jalal Kamali, M.R. and Sharifi, H.R. 2010. Variation in developmental stages and its relationship with yield and yield components of bread wheat cultivars under field conditions II: Yield and yield components. Seed and Plant Production Journal, 26(1), pp.1-23. (in Persian).
Nuttall, J.G., Barlow, K.M., Delahunty, A.J., Christy, B.P. and O’Leary, G.J. 2018. Acute high temperature response in wheat. Agronomy Journal, 110(4), pp.1296-1308. DOI: 10.2134/agronj2017.07.0392
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