Ali Shayanfar; Farshid Ghaderifar; Rahmatollah Behmaram; Afshin Soltani; Hamidreza Sadeghipour
Abstract
Secondary seed dormancy is known as the major reason for seed persistence of canola (Brassica napusL). Volunteer’s rapeseeds emerging from the soil seed bank can lead to unwanted gene dispersal to other plants after breaking secondary seed dormancy. At the current study, secondary dormancy was ...
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Secondary seed dormancy is known as the major reason for seed persistence of canola (Brassica napusL). Volunteer’s rapeseeds emerging from the soil seed bank can lead to unwanted gene dispersal to other plants after breaking secondary seed dormancy. At the current study, secondary dormancy was induced in 41 lines and 5 cultivars of canola under laboratory condition with using polyethylene glycol 6000, during 14 days and secondary seed dormancy recorded. This study was conducted as a randomized complete design. High germination percentage was observed at the all lines and cultivars (higher than 94%), and they were classified at five groups included very low, low, medium, high and very high secondary dormancy using cluster analysis. Among different lines, five genotypes were included at the very low group and two genotypes were included at the very high group. The other lines were placed in average and low groups. It was observed that five varieties (RGS003, Zarfam, Hyola401, Hyola308 and Hyola50) had average secondary dormancy (40-60%) that was related to breeding ignorance about secondary dormancy during seed production process. Lines classification based on different levels of secondary dormancy helps seed producers to select lines with low levels of secondary dormancy along with high yield and other characteristics, in order to deal with problems in seed producing process.
Hemmatollah Pirdashti; Behrouz Mahmoudi; Mohammad Yaghubi
Abstract
A field experiment was conducted to investigate the spatial distribution of weeds at the Sari Agricultural Sciences and Natural Resources University in 2011. Field was divided into 42 grids (1.5×1.5 feet) then all samples were taken from grids intersection points before corn planting, after harvesting ...
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A field experiment was conducted to investigate the spatial distribution of weeds at the Sari Agricultural Sciences and Natural Resources University in 2011. Field was divided into 42 grids (1.5×1.5 feet) then all samples were taken from grids intersection points before corn planting, after harvesting and ear emergence stage. Weed maps and semi variance analysis carried out using RW99 and Gs+ softwares. The results showed that the highest amount of weed population belongs to prostrate pigweed, nutsedge and redroot pigweed, respectively. There was a strong and moderate spatial correlation as spherical and exponential variograms model at all stages of sampling. The seed banks were patches with different sizes and densities. Seed bank patchy pattern at the beginning of season was in accordance with seed bank at the end of season. Knowing the seed bank density, we can forecast weed seedling density during crop growing season.