محمدرضا لک

The red bean Ofogh cultivar introduced to Iran in 1994 under the name of Line D81083 from the International Center for Tropical Agriculture (CIAT) and was evaluated in several experiments with breeding, agro-techniques, plant protection and onfarm aspects. This cultivar with grain yield of 2324 kgha-1 had 11% higher yield compared to the Goli check cultivar in evaluation of adaptability of red bean cultivars in Khomein region. Based on its grain yield and also due to early maturity, plant stand type, excellent grain size and good marketing this line was selected for further studies. Ofogh cultivar had the lowest yield reduction under drought stress conditions and had a lower susceptibility index and higher drought tolerance index compared to Goli check cultivar. Also, with an efficiency of 0.28 kgm-3 under drought stress conditions, it had a good water use efficiency. This cultivar is resistant to bean common mosaic virus disease. Also, it is 20-25 days early mature than conventional red bean cultivars and cut down at least four irrigations, where under flood irrigation conditions it will save at least 3400 m3 of water consumption. This cultivar is recommended for areas where cultivation of beans is not possible due to early autumn cold damage, or in the areas where bean planting time is delayed in spring due to coincidence with irrigation of autumn crops such as wheat, barley and canola.

Bean root rot disease caused by Fusarium solani f. sp. phaseoli is one of the major diseases associated with beans. In order to evaluate effective agronomic strategies to control this disease, an experiment has been carried out as a factorial split plot arrangement in randomized complete block design with three replications over two years. The experiment takes place in a farm with a history of infection with the causal agent of root rot disease at the Bean Research and Education Campus of Khomein City. Type of cultivation includes flat-striped method, furrowing method without hilling up, furrowing method with one time hilling up, and furrowing method with two times of hilling up in main plot. Also, the two red bean cultivars involve Ofogh and Yaghout and the three plant density include 20, 30, and 40 plant/m2 in a sub-plot with factorial arrangement. Results show that among the studied cultivars, the highest grainyield and minimum bean root rot severity belong to Yaghout cultivar. Additionally,, increasing the plant density adds to the severity of Fusarium root rot disease. Among the different methods of planting, the least root rot severity occurs in the furrowing method with one time of hilling up, while the highest grain yield is obtained from cultivation of Yaghout at a density of 30 plant/m2 in furrowing planting method with one time hilling up. Therefore, in those areas where the occurrence of this disease is very potential, it is necessary to change the method of bean planting from flat to furrowing method and hilling up the plants.

Common bacterial blight (CBB), caused by Xanthomonas axonopodis pv. phaseoli (Xap), is one of the major diseases in common bean fields leading to significant losses in yield and seed quality. Application of resistant varieties is the effective disease management. In this study, 15 bean genotypes with the Sadri cultivar as a check varaiety were cultivated in the field of Agricultural and Natural Resources Research Center of Markazi province during 2015 and 2016 which were inoculated with bacterial suspension (107 cell/ml) before flowering stage. The resistance of genotypes was assessed in the pre-physiological maturity stage. The results showed that CBB reduced yield average 33.2% in the studied lines. Also, yield components including number of pods per plant, number of seeds per pod and one hundred seed weight reduced 28.9%, 17% and 15.6% respectively.Finally, based on factor and cluster statistic analysis, five bean lines with the highest geometric mean productivity and steress tolerance index and the lowest stress susceptibility index were selected. VAX3 and Ks31118 genotypes were released as CBB resistant red bean varieties due to their marketability and suitable grain color. Also VAX1, VAX5 and VAX6 lines can be used as the parents in bean hybridization programs to release resistant varieties to this disease.

Common bacterial blight (CBB) caused by Xanthomonas axonopodis pv. phaseoli is a serious disease of bean fields in Iran and the world. Chemical control of CBB is inefficient, therefore the use of resistant genotypes with stability production is the most suitable alternative. Stability and adaptability of 26 bean genotypes yield in the presence and absence of CBB were evaluated in Agricultural Research and Natural Resources Center of Markazi Province, in 2007 and 2008 using regression analysis, the additive main effects and multiplicative interactions (AMMI) and muir methods. The best genotype in regression analysis, based on yield, regression coefficient and deviation from regression was 21407. In AMMI analysis, the first two interaction principal component axes (IPCA1 & IPCA12) explained 90% of the genotype×environment interaction. Biplot of yield mean and IPCA1 showed that genotypes 21407 and 21275 were the most stable with high yield. In muir method, 21% and 79% of the genotype×environment interaction belonged to heterogeneous variance (HV) and imperfect correlation (IC), respectively. In this method the genotype 21410 had the least total sum of squares of genotype × environment interaction, so it was the most stable genotype. According to all results, the best genotype was 21407 based on stability, yield and resistant to CBB.

Line G11867 was first introduced in Iran together with 206 other white, chitti and red beans lines through CIAT, and was tested in different breeding experiments from 1992 to 1999. It was selected as a superior line in all experiments. In 2001 this line was evaluated with other six lines for drought tolerance, and it was found to be more tolerant than cv. Daneshkadeh the check cultivar. Line G11867 was evaluated as a resistant line to CMV but susceptible to BCMV and BYMV. It was also resistant to two spotted mite in several experiments. In farmers farms its yield (2700 kgha-1) was more than the local check cultivar (1986 kgha-1). Its cooking quality was also evaluated good, compared to the newly introduced cultivars Pak and Shokofa. Due to high yield, drought tolerance and resistance to CMV and mite, line G11867 was officially introduced as a new cultivar for cultivation in cold regions of Iran in 2010.

To study the effect of planting date on root rot disease caused by Fusarium solani f.sp. phaseoli of Chitti bean (Phaseolus vulgaris L.), an experiment was conducted in Khomein Bean Research field Station in 2004 and 2006 cropping seasons. This experiment was arranged as split plot in a randomized complete block design with three replications. Three chitti bean genotypes (local Khomein, Talash, and COS16) were sown in four different planting dates (10 May, 25 May, 09 June, and 24 June). Combined analysis of variance showed that the effect of planting date on seed/pod, seed/plant, 100 grains weight, seed yield and root rot disease severity was significant at the 1% probability level and on pods/plant at the 5% probability level. Effect of cultivar on pods/plant, grains/plant, 100 grains weight and root rot disease severity was significant at the 1% probability level and on grains/pod and grain yield at the 5% probability level. Planting in 09 June and COS16 genotype produced the highest seed yield. Delaying planting date decreased disease severity. COS16 and local Khomein genotypes had the least and the highest disease severity, respectively.

To understand the role of relative humidity rate, host genotype, inoculation method and growth stage in epidemiology of bean common blight, two greenhouse experiments were carried out monitoring epiphytic population size of Xanthomonas axonopodis pv. phaseoli (Xap) and disease severity. The result showed significant differences among genotypes, inoculation methods and growth stages for epiphytic population size and sam effects except genotypes for disease severity. The epiphytic population size was significantly higher on spray inoculated Khomein cultivar of bean during flowering (R6). However, the relative humidity rates did not significantly affect population dynamics of epiphytic Xap and the disease severity. Two field experiments were also carried out to determine the effects of irrigation systems (furrow irrigation and overhead sprinkler irrigation), inoculation method, growth stage and their interactions on epiphytic population size of Xap and disease severity. The result showed that the epiphytic population size and disease severity were higher on spray inoculated plants irrigated with overhead sprinkler system during pods filling (R8). In this study, a significant positive correlation was found between epiphytic population size of Xap and bean common bacterial blight severity.

In orther to determine the critical period for weed control in the Chitti bean (Phaseolus vulgaris) line KS-21467 a field study was conducted at the Bean Research Station of Khomein by a randomized completele block design in 2001 and 2002. The treatments included weed free and weed infested period until 20, 28, 36 and 44 days after planting (DAP) with two weed free and weedy checks. The results indicated that the critical period at 5% allowable yield loss was 20-53 DAP (between first-trifoliate and flowering stages) in 2001 and 35-51 DAP ( between blossom and flowering stages) in 2002. Weed dry weight decreased averaglly 81% in weed-free period until 44 DAP compared to the weedy check. Yeild decreased averaglly 63% in weedy check compared to the weed free check. Weed competition increased the height of bean, wherease 100-seed weights and the number of seeds per pod were not substantially affected. There was a negative and significant correlation of weed dry weight with the number of pods per plant, the number of seeds per plant and yeild.