فصلنامه علوم زراعی ایران
سال بیست و دوم شماره 2 (پیاپی 86، تابستان 1399)

Over the past 50 years, thousands of rice varieties have been introduced by plant breeders to agricultural communities all over the world. Despite the improvement of attributes such as grain yield and tolerance to biotic and abiotic stresses, a significant portion of farmers still prefer local varieties over the improved cultivars. The main reasons for this perference are the absence of a direct relationship between farmers and plant breeders, the lack of knowledge about the needs and preference of agricultural societies, the differences in crop growth conditions at agricultural research stations and marginal farmerschr('39') fields, and the different agroecological conditions among target agro-ecological regions. In addition, local varieties have high quality and stable grain yield under different conditions and over cropping seasons. Over the past two decades, the concept of participatory plant breeding (PPB) has been developed in collaboration with crop breeders, farmers, traders and consumers to improve the system of introducing new crop varieties. In this approach, there is a direct relationship between farmers/stakeholders and plant breeders. The released cultivars using participatory plant breeding programs, have higher grain yield and dyield stability, and increase farmers’ income. In addition, they enhance genetic diversity and accelrate the adoption process of new cultivars by farmers. Participatory breeding programs in close collaboration with farmers/stakehilders can be very useful, and may cahne the future of conventional breeding programs. Relaesing two new rice improved cultivars (Gilaneh in 2016 and Anam in 2019) with farmers participatory is an example of the rice breeding success story of participatory rice breeding program in Iran.

In order to study the genetic variability based on the physiologic and drought tolerance indices of 20 genotypes of durum wheat, an experiment was carried out in research farm and physiology laboratory of Agricultural and Natural Resources Campus of Razi University of Kermanshah, Iran, in a randomized complete block design with three replications under stress and non-stress conditions in 2013-2014. The results of analysis of variance for different agronomic, physiological and biochemical traits showed that the effect of genotype on the characteristics of water stored in cut leaves, water use efficiency, stomata conductance, chlorophyll b, total chlorophyll, grain yield, activity of catalase enzymes, peroxidase and superoxide dismutase were significant. Comparison of mean of different traits showed that genotypes 20, 5, 3, 1, 12 and 13 had the highest values. The correlation analysis in drought stress revealed that the grain yield with chlorophyll b and total chlorophyll as well as relative water content had a significant positive correlation with photochemical efficiency of photosystem II. Significant negative correlation was observed between the water stored trait of cut leaves and the level of activity of the enzyme superoxide dismutase. There was a significant positive correlation between chlorophyll a content with chlorophyll b and chlorophyll content as well as between chlorophyll b and total chlorophyll. The GGE-BIPLOT showed that the genotypes 5, 6, 20, 9, 2, 3, 10, 4, and 19 were identified as superior genotypes for studied traits. Such comprehensive information on genotypes is important for converting them to cultivars and introducing them to farmers, as well as choosing parents for hybridization.

Weeds are one of the most important factors in reducing yield in legumes crops. Therefore, awareness of the interaction between weeds and crops as well as identification of their spatial variation pattern in the field is important. To investigate the the effect of  weeds on seed yield of lentil, and also to study the spatial distribution pattern of weeds under rainfed conditions, a field experiment was conducted in research field of agricultural and natural resources campus, Razi University, Kermanshah, Iran, in 2016. Systematic samplings and measuremnts weeds characteristics (density, canopy percentage, height and dry weight) and lentil (canopy percentage and seed yield) were carried out in two stages; pre-flowering and physiological maturity of lentil. The relationships between weeds and lentil were studied using regression and maps of weeds and lentil traits using Kriging interpolation method. The results showed that by increasing the density and canopy percentage of weeds from 0 to 10 (plants.m-2 or percentage), the seed yield of lentil decreased by 6.2 and 6.7 g.m-2, respectively. Furthermore, increasing weeds dry matter from 0 to 10 g.m-2 led to a decrease in lentil seed yield by 2.4 g.m-2. The spatial distribution maps also clearly showed the spatial variations of seed yield under the influence of weeds. In conclusion, the results of this study showed that spatial maps of weeds and lentil traits distributionas well as conventional statistical methods are complementary and accurate method for better understanding of the relationships between them.

Comparative genomics has revealed a high degree of collinearity between related species, which allows transferability of interspecies and intergenus   markers. The aim of this study was to examine the transferability of barley microsatellite markers among species of Triticum and Aegilops genus for determination of their genetic relationships. The experiments was carried out in faculty of agriculture, university of Tabriz, Iran, in 2016. Among 165 evaluated barley microsatellite primer pairs in 40 genotypes from nine species of Triticum and Aegilops genus, 62 (37.57%) showed successful amplification at least in the genome of one species and 50 (30.3%) were polymorphic. Using 50 polymorphic primer pairs, 223 alleles were amplified and number of alleles varied from 2 to 14 with an average of 4.46. The mean of polymorphic information content and genetic diversity were 0.55 and 0.6, respectively. The studied genotypes were assigned into four groups using Nieghbor-Joining clustering algorithm and Guckes Cantor evolutionary distance coefficient. The species of Triticum and Aegilops genera were grouped separately, and within each genus, grouping was in accordance with their genome structure. In principal coordinate analysis, two first coordinates explained 24.63 and 21.86% of molecular variation, respectively, and distribution of the genotypes based on two first coordinates was in concordance with grouping of cluster analysis. The results indicated that the transferable barley markers could be successfully utilized in wheat and its wild relatives genetics and breeding studies.

Irrigation water deficit is an important factor that affect rice production in the world as well as Guilan province in Iran. Intermittent irrigation method can be applied to compensate for the water shortage in rice growing areas, however, it would affect other crop mangement practices such as fertilizer application and mangement. Therefore, this experiment was conducted to determine optimum fertilizer nitrogen requirement in different irrigation regimes using split plot arrangements in randomized complete block design with three replications in Rice Research Institute, Iran in 2015 and 2016 growing seasons. Irrigation regimes included at five levels (permanent submergence, intermittent irrigation with 5, 8, 10 and 15 day intervals) were assigned to main plots and nitrogen fertilizer  at sixlevels (0, 30, 45, 60,75 and 90 kg Nha-1 from urea source) were randomized in sub-plots. Planting, crop husbandry and harvesting pratcices were done according to RRII recommendations. The results showed that effects of irrigation regime and nitrogen fertilizer application rates were significant on the grain yield, biological yield and most of the studied traits. Among irrigation regimes, intermittent irrigation of five days interval with 3278 kg.ha-1 had significantly higher grain yield. The highest grain yield (3388 kg.ha-1) was also obtained from application of 90 kg N.ha-1. The irrigation water consumption in intermittent irrigation with five days interval was 379 m3.ha-1 less than permanent submergence irrigation. Regarding to this fact, that highest grain yield (4335 kgha-1) and highest water productivity (688 g.m-3) beloged to intermittent irrigation with five days intervaland 90 kgN.ha-1 application. This combination of irrigation interval and N fertilizer application rates can be recommended for heavy textured soils of paddy fields in Guilan province.

Selection of adapted genotypes with high seed yield and yield stability is the goal of soybean breeding programs. To evaluate the adaptability and seed yield stability of soybean promising lines, 19 promising lines and cv. Williams as check were evaluated using randomized complete block design with four replications in four locations: Karaj, Gorgan, Moghan and Khoramabad in Iran during two growing seasons (2013 and 2014). GGE biplot analysis was employed to evaluate the adaptability and seed yield stability. Combined analysis of variance showed thatyear, location, genotype, year × location, year × genotype, location × genotype and genotype × location × year interaction effects were significant on studied traits. The contribution of year, location and genotype variance to total variance was 0.01, 0.60 and 0.02, respectively, indicating considerable contribution of location variance. The first two components of PC1 and PC2 explained overall 58% of total observed variation of genotype and genotype × environment (G + GE). In this study, three mega-environments were identified. The first mega-environment included: E2 (Karaj 2014), E5 (Moghan 2013) and E8 (Gorgan 2014) and G16 was the superior genotype in this mega-environment. The second mega-environment included: E3 (Khorramabad 2013) and E4 (Khorramabad 2014) and G8 was the superior genotype in this mega-environment. Third mega-environment consisted: E1 (Karaj 2013) and E7 (Gorgan 2013) and G17 was the superior genotype in this mega- environment. Biplot analysis showed that genotypes: G17 (L85-3059) with 2702 kg.ha-1 and G16 (L12/Chaleston × Mustang) with 2750 kg.ha-1 were highly adapted genotypes with high seed yield and yield stability. The E7 environment (Gorgan, 2013) was the most desirable environment in respect to its discriminating ability among soybean genotypes and the best representative of the target environments.

In order to quantifying emergence pattern of rapeseed weeds, this experiment was conducted in 40 plots (40 quadrates at Agricultural Sciences and Natural Resources University of Khuzestan, and 30 fields of Bavi (30 quadrates), Ahvaz, Iran, in 2016-2017 growing seasons was monitored, counted and recorded weekly. Three different emergence pattern of nine weed species were identified, Prickly lettuce (Lactuca serriola L.) and Wild mustard (Sinapis arvensis L) were identified as early-emerging species. Also salt sandspurry (Spergularia marina L.) and furrowed melilot (Melilotus sulcatus), were categorized as late- emerging species. However, five species including; mallow (Malva spp), rigid ryegrass (Lolium rigidum), sea beet (Beta vulgaris subsp. maritima), milk thistle (Silybum marianum L) and nettle-leaved goosefoot (Chenopodium murale L) were identified as medium-emerging species. Estimation of GDD50 (time required to reach 50% emergence) showed that the minimum (323.62 ℃d)) and maximum (608.93 ℃d) growing degree day required by Lactuca serriola and Spergularia marina (L.), respectively. Whereas, 10% emergence of Spergularia marina and Melilotus sulcatus required 362.42 ℃d and 426.37 ℃d, respectively. The results of weeds emergence pattern in rapeseed crop showed that the soil herbicides with longer half-life should be applied, and the application of post emergence herbicides and agronomic practices such as plant density and competitive ability of rapeseed cultivars are necessary components in integrated weed management.