جستجوی مقالات مرتبط با کلیدواژه "fertility" در نشریات گروه "زراعت"

Early vigor, stress resistance, uniformity, high yield, and breeder right protection have turned hybrid cultivar development into the most successful breeding strategy in rapeseed (Brassica napus L.). The goals of this research were to develop the first CMS based rapeseed hybrids in Iran and to evaluate their performance and fertility. The effect of different traits on yield increasing of hybrids was also studied. Seven CMS lines were crossed with R2000 (a restorer-line) and the seed yield of hybrids was tested using a randomized complete block design with three replications in 2019-2020 and 2020-2021. Three of hybrids with 4.64, 4.40, and 4.38 tons per hectare, showed considerable yield and were significantly different than Nilufar, Neptune, and Nima (3.44, 3.37, and 3.30 tons per hectare, respectively), as check cultivars. R2000×A8 demonstrated the highest heterosis (34.71%) to high-check cultivar. All hybrids obtained were normal in terms of fertility, having no male-sterile flowers. Based on the results of principal component analysis and cluster analysis, the simultaneous increase in the number of pods per plant and the thousand seed weight, together with crossing the more distant parents will lead to more high yielding hybrids. The promising hybrids with high yield and remarkable fertility could be released as new cultivars after passing adaptability and stability experiments.

Fertilizer management is one of the most important managements to improve production and also to minimize its harmful effects on the environment. The aim of this study was to investigate the effect of optimal and conventional application of nitrogen (N), phosphorus (P) and potassium (K) on the yield of low-yielding (Deylamani and Hashemi) and high-yielding (Fajr and Shirodi) rice varieties. The experiment was conducted as a split plot in a randomized complete block design three replications at a research farms of Sari University of Agricultural Sciences and Natural Resources in 2019. In the absence of any of N, K and P fertilizers, yield of Shiroodi cultivar was 5458, 8399 and 9926 kg ha-1, respectively, and yield of Fajr cultivar was 4894, 7364 and 8903 kg ha-1, respectively. In low-yield cultivars, in the absence of any of N, K and P fertilizers, yield in Hashemi cultivar was 2969, 5134 and 4925 kg ha-1, respectively, and yield in Deylamani cultivar was 3028, 5408 and 5384 kg ha-1, respectively. Optimal application of N, P and K fertilizers caused a significant increase of 82, 65, 55 and 34% of yield in Shiroodi, Fajr, Hashemi Tarom and local Tarom cultivars, respectively, compared with the current application of these three nutrients. The results showed that a suboptimal application of nitrogen, phosphorus and potassium fertilizers is a main limiting factor for rice production, and improving the amount and split application of these fertilizers simultaneously can increase yield by 59% compared to their current application in the region.

One of the most important factors in the production of high yield of plants is the presence of soil nutrient elements. Therefore, the accurate study of the amount of available elements such as macronutrients and micronutrients in soil is essential for the production of important products such as maize. For this purpose, preparing the soil fertility map of four basins agricultural in Golestan province was examined by Geographical Information System (GIS), Fuzzy logic and Analytic Network Process (ANP) for maize cultivation.

This research was carried out in four basins of Qaresoo, Qarnabad, Mohammadabad and Zaringol in Golestan province. The information of 858 sampled points were used for the preparation of soil elements layers including K and P available, total N, Ca, Mg, Fe, Zn, Cu and Mn available of the soil. First, the raster layer of each element was prepared in ArcGIS10.4 media by ordinary Kriging method in the agricultural lands of the study area. Then, with the help of fuzzy functions, each fuzzy standardization element map was prepared, the maps for each element were weighed using ANP and the soil fertility map was prepared by the layers' overlay the soil fertility map was prepared. In order to adapt the layers produced with the nutritional needs of maize, nutritional requirements of this plant were determined using the scientific resources. Finally, the final layer was divided into five categories of very high fertility, high, moderate, low and very low.

The results showed, the fuzzy value of the agricultural land in the study area was between 0.30 and 0.78. 119771.47 ha, equivalent to 59.87% of the studied area, had a moderate fertility that was more in the middle part of the study area and 80212.65 ha, equivalent to 40.9% had low fertility that was more in the north and south. 84.24 ha, equivalent to 0.04 percent had high fertility and two categories of very low fertility and very high fertility had no share of the study area. Among the basins, Zaringol basin had the highest fertility and the Mohammadabad basin had the lowest fertility. The mean fuzzy value showed, the elements of Mn and K had the highest fuzzy value and the elements of Ca and Zn had the lowest fuzzy value, respectively. The elements of K, P, N, Ca, Mg, Fe, Zn, Cu and Mn reduced the fertility value of the studied lands' area 69.38, 76.02, 96.98, 94.68, 47.81, 49.10, 96.98, 69.57 and 30.28%, respectively.

The results of the fertility zoning of the four studied basins with the help of fuzzy logic and ANP for maize cultivation showed, almost the entire study area (with the exception of 84.24 ha) faced with problems in terms of fertility. Zaringol basin was the most fertile basin for corn cultivation and Qaresoo, Qarnabad and Mohammadabad basins were in the next rank of fertility, respectively.

Rice is one of the oldest cultivated crops. Anatomical changes in plants under environmental stress can reduce the vascular bundles area such as Xylem area; as a result, these changes can protect cells from death and dieback. There was a difference in terms of pollen germination at times after anthers’ opening. Variety Minyhui 63 had the highest germination rate (85%) at time 0 or immediately after anthers’ opening; but for variety Rufipogon with lower germination rate (60%), 50% of pollens were alive after 12 min (longer). The lowest germination rate (34%) was observed in hybrid varieties with an average longevity that even after 40 min more than 50% were alive. Simultaneously between opening of florets, anthers causes high self-pollination in rice, but flowering time under stress can postpone the turgidity and growth of pollens. Matsui and Hisashi (2003) reported that positive correlation between the number of pollen on stigma and morphological characteristics.

The current research was done for recognizing the impacts of different planting dates on morphological traits in five cultivars of rice in Khouzetan. An experiment was carried out by 2 factors as split-plot using randomized complete blocks design with three replications in agricultural research station. 3 planting dates (2.15, 3.5, and 3.25) in the main plots and 5 sorts of rice including Hoveize and hamer (heat tolerance), red Anbori and Champa (sensitive), and Daniel (semi-tolerance) were arranged in the sub-plot.

The result of combined analysis showed the reaction of cultivars were completely related to planting dates and significant difference were observed for interaction effects in %1 and %5 probability level. The highest anther length, stigma length and style length were related to planting dates 1, and 3. Meanwhile, the planting dates with longer anther and stigma had more pollen number. But among cultivars the reaction was completely different, and cultivars with longer anther had shorter stigma. Also cultivars with increasing of pollen and anther surface and pollen number and development of pollen nutrition respectively can prevent of pollen abortion and yield reduction. The highest grain yield was related to the suitable planting date (3.5) that had %62.5 and %18/1. Production increase with respect to. 2.15 and 3.25. Because the second planting date had the suitable stigma, style, anther length and so anther width and more pollen number on the stigma that can increase pollen germination and production. Among the sorts, Hoveize was superior than others and it had higher yield with 50.9% and 36.3% respectively than 2 sorts that are sensitive to heat: red Anbory and Champa. The shorter growth duration (10-13 days) with respect to other cultivars and escape of high temperature was adaptation mechanisms of Hoveize. On the other hand cultivars had different reaction in related to temperature condition.

Therefore, we hope to increase production under stress condition whereas breeding objectives concentrate on the lowering vascular bundles and control length of florets components to increase contacts between pollen and florets and finally, fertility.