Introduction
Cowpea (Vigna unguiculata L.) is a valuable food legume from the Fabaceae family. This crop originated from West Africa (Nigeria) and was then transferred to the Middle East and Europe. Cowpea is suitable for cultivation in tropical regions. Iin addition to its multipurpose uses (green pods, dry seeds, animal feed), it also has high agronomic value. Despite breeding research worldwide to increase cowpea production, its yield is low in most growing regions. Therefore, to increase the yield, along with breeding activities, more studies should be conducted in the field of agronomic management. One of the important factors in farm management and increasing the production of legumes, including cowpea, is the use of micronutrients, especially iron.
Materials and Methods
In the present study, the responses of 12 cowpea lines (C1 to C12) along with the Mashhad cultivar to the application of iron nanofertilizer were investigated in four regions of Iran (Karaj, Dezful, Khomein and Shiraz). The experiments were conducted in a strip plot based on a randomized complete block design with three replications in 2023. Genotypes were placed in horizontal plots and treatments of using or not using iron nanofertilizer were placed in vertical plots. Some morphological traits including yield and yield components of genotypes were evaluated in different environments.
Results and Discussion
The results showed that the effects of location, nanofertilizer and genotype on all studied traits were significant. The interaction effect of location and nanofertilizer was significant on all traits except biomass, harvest index and 100-grain weight, but the interaction effect of location and genotype was significant on all traits except the number of grains per pod. The interaction effect of genotype and nanofertilizer was significant on all traits except plant height, biomass and grain yield. All traits, except the number of seeds per pod, were significantly affected by the three-way effect of location, genotype and nanofertilizer. Lines C4 and C5 were the earliest and the most late-maturing genotypes, respectively. The highest biomass yield of 3810 kg ha-1 was related to the Mashhad cultivar, and the biomass yield in all lines was lower than that of the Mashhad cultivar. Plant height and number of branches per plant varied from 55.9-72.7 and 5.4-7.4, respectively. Only four lines, along with the Mashhad cultivar, had a grain harvest index higher than the average. The highest grain harvest index was related to C1 line (38.77%). All 13 genotypes studied responded positively to the use of iron nanofertilizer and had better growth compared to the conditions of no nanofertilizer use. The highest average percentage increase was related to the number of seeds per plant (27.25%). The use of iron nanofertilizer accelerated the maturity of the genotypes. In the absence of iron nanofertilizer, the number of pods per plant and the number of seeds per pod, and consequently the number of seeds per plant, were significantly lower than when iron nanofertilizer was applied. In line C11, although the values of these traits were lower than the average of the genotypes in the absence of iron nanofertilizer, it showed the greatest response to iron nanofertilizer application. Yield components (number of pods per plant, number of seeds per pod and 100 seed weight) showed a significant increase (17.4%, 8.8% and 3.2% respectively) under the influence of iron nanofertilizer application. Grain yield also increased by 10.8%. In accordance with our experimental results, it has been reported in various studies that the use of nanofertilizers significantly increases the yield of crop plants compared to treatments without the use of nanofertilizers. The main reason for this is the improvement of the growth of plant components and metabolic processes such as photosynthesis, which causes greater accumulation of photosynthetic products and their transport to the economic organs of the plant.
Conclusion
Based on the environmental index, the evaluated locations differed from each other. Accordingly, Dezful region had the highest value of environmental index. Line C1, along with lines C4 and C11, were the best genotypes. Although the use of iron nanofertilizers improved the growth and development of the studied genotypes, since there are limited reports on the biological consequences of nanofertilizer use and their absorption by plants, and numerous questions remain about the fate and behavior of nanomaterials in plants, the use of these types of fertilizers should be done with more caution. |
