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Effect of seeding rate on relationships between plant traits, seed yield and seed oil content of rapeseed (Brassica napus L.) cultivars
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Amir Vahdatirad   , Rasool Mahmoudi |
| adineh group & Senior expert of Research and Development, Fadak Adineh Agroindustry, Adineh Group, Tehran, Iran |
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Abstract: (89 Views) |
Introduction: Rapeseed is one of the major oilseed crops in the world. Increasing the seed yield and oil content of rapeseed is important for the production of rapeseed oil. The maximum seed yield is achieved in the optimal plant density. By reducing the plant density, it is partially compensated by the increase in number of secondary branches, biomass, while in high density, rapeseed plants are often prone to increase the incidence of disease (Rondanini et al., 2017). Determining the optimal density in crops depends on many factors such as plant type, soil fertility, available water and environmental conditions (Hiltbrunner et al., 2007). Rapeseed genotypes differ from each other in terms of the number of seeds per silique, the number of siliques per unit area, seed weight, and the number of secondary branches. The objective of the present experiment is to obtain this information and determine the appropriate plant density to obtain the highest seed yield and to identify the role of yield components in production and the relationships between them in new rapeseed cultivars.
Materials and Methods: The seedinging rate was determined based on the thousand seed weight of rapeseed cultivars using a fine seed machine and 1 kg., 2 kg, 4 kg and 8 kg.ha-1 seed were used. The rapeseed cultivars used were Architect, Rohan and Okapi. Factorial arrangement in randomized complete blocks design with three replications was used. The experiment was carried out in research farm of Fadak Agro-industry Company in Markazi province, Iran in 2021-22 and 2022-23 growing seasons. Phenological traits including days to flowering days to maturity, seed filling duration, seed filling fraction (the ratio of seed filling duration to the total growth duration from seeding to maturity) and plant height were measured and claculted. Seed yield and its component, including; number of secondary branches, thousand seed weight, number of silique.plant-1, number of seed.silique-1, were measured on randomly harvested 20 plants from each experimental plot and calculating the average. Seed yield was obtained with harvesting from 50 m2 in each plot. Seed oil content was measured using an NMR spectrometer (ISO 10565, 1998). Analysis of variance was performed using SAS 9.1 software, and relationship between traits was studied using Excell 2003 software. LSD test, at the 5% probability level, was used for means comparison.
Results: Results showed that days to flowering varied from 198.7 to 205.8 days and had a decreasing trend with the increasing of seeding rate. The longest seed filling duration (30.5 days) was recorded for cv. Architect. The shortes seed filling duration (24.3 days) belonged to cv. Okapi at the seeding rate of 2 kg.ha-1. The 1000 seed weight of the cv. Architect, cv. Rohan and cv. Okapi were 5.22 g, 4.36 g and 3.39 g, respectively. With the increase of seeding rate, 1000 seed weight decreased from 4.56 g in 1 kg.ha-1 to 4.1 g in 8 kg.ha-1 seeding rates. The highest number of secondary branches in the cv. Architect was obtained at 1 and 2 kg.ha-1 seeding rates. The highest seed yield in cv. Architect (4731 kg.ha-1) was obtained in seeding rate of 4 kg.ha-1. The plant height decreased from 172 to 152.6 cm. with increasing seeding rate.The number of seed.silique-1 had a downward trend. With the increase in seeding rate, the seed oil content showed a significant upward trend. Seed yield significantly correlated with 1000 seed weight, number of secondary branches, plant height and seed oil content.
Conclusion: With the increase in seeding rate, seed oil content increased and this result can be related to the increase in the number of main stems with the increase seeding rate. Seed filling fraction (the ratio of seed filling duration to the total growth duration from seeding to maturity) and its positive and significant correlation with yield traits such as seed yield, 1000 seed weight and seed oil content showed that the long seed filling duration in addition to the early flowering is a desirable attributes. According to the results of this experiment, the optimum seeding rates for cv. Architect, cv. Rohan and cv. Okapi were 2, 4 and 8 kg.ha-1, respectively. In new rapeseed cultivars, cv. Architect and cv. Rohan, early flowering, longer seed filling duration and higher seed filling fraction may have important roles in achieving higher seed yield.
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| Keywords: Rapeseed, Seed filling duration, Seed oil content, Seed yield and 1000 seed weight |
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Full-Text [PDF 918 kb]
(52 Downloads)
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Type of Study: Scientific & Research |
Subject:
Special
Received: 2024/01/13 | Accepted: 2024/06/23 | Published: 2024/12/30
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