International Journal of Plant Production
Volume:6 Issue: 3, Jul 2012

Oil concentration (OC) in canola (B. napus L.) is determined during seed filling period (SFP), and the variation in OC is greatly related to environmental conditions during that period. To determine factors affecting OC in canola, 12 field experiments were conducted at Agricultural Research Station of Gonbad, Iran, during 2000-07. The experiments were carried out under different growing conditions. The regression functions were fitted to the data of each group of genotypes, over years and experiments. Increasing SFP was a determinant factor for increasing OC. Oil concentration was affected by the duration of SFP, which was maximized when plants of both genotypes (open pollinates and hybrids) were exposed to lower temperatures. There was a linear negative relationship between air temperature during SFP and OC. High temperatures, accelerated the rate of plant development, lowered the length of SFP, and reduced OC potential. In both group of genotypes, the variation of OC was explained by rainfall during SFP, and temperature and radiation interactions during the period, as showed by photothermal quotient (PTQ). There was a positive logarithmic relationship between PTQ during SFP and OC. The relationships of OC with duration of SFP, and temperature, PTQ and rainfall during SFP over years, sowing dates and genotypes showed that these variables are generally applicable in canola OC determination.

Plastic mulch increased minimum temperature of soil, accelerated plant height, early growth, early yield, and bring satisfactory weed control without any application of herbicides. This experiment was laid out on three-factorial Randomized Complete Block Design with three replications during 2008-2010 at the National Rice Research Institute, Rasht, Iran using three kinds of mulches (Transparent and black PE and rice straw). Results showed that garlic total yield, bulb ash percent, TSS, vitamin C and flavonoids content were affected by mulching. Although mulching could improved some quality indices in garlic but no effect on forcing was observed. Due to two years experiment and interaction between year and mulches the usage of rice straw in rainy and cool season and plastic mulch in low rain fall and warm season recommended increasing garlic quality as second crop in rice field.

Field experiments were conducted to determine the effects of organic and inorganic amendments on weed suppression in sweet maize cultivation (Zea mays L.). A randomized complete block design was employed with four replicates per treatment with each organic amendment used at half (x/2), single (x=10 t ha-1) and double (2x) rates (organic fertilization: cow manure, poultry manure and barley mulch; synthetic fertilizer (240 kg N ha-1: 21-0-0); and control). The highest number and dry weight of weeds were recorded for double cow manure and chemical fertilizer treatments. The cow manure treatments promoted weed emergence and growth proportionally to the rate of application (x/2

The effect of aqueous smoke extract, derived from Tanacetum parthenium, on in vitro plantlet regeneration from rapeseed (Brassica napus L. cv. Topas) microspore-derived embryos (MDEs) was evaluated in this study. Inoculation of rapeseed MDEs with the smoke-extract dilutions (1:250, 1:500, 1:1000 and 1:2000) for various times (5, 10 and 15 min) significantly enhanced the percentage of regenerated plantlets from these embryos and also decreased the callogenesis percentage in these explants. The root length and shoot length of inoculated MDEs were significantly improved with all smoke-extract dilutions except for dilutions of 1:100 and 1:10. Application of smoke-extract solutions (1:1000, 1:500, 1:250 and 1:100) in B5 regeneration medium significantly enhanced the plantlet regeneration from rapeseed MDEs compared to control cultures. Furthermore, use of smokeextract solutions in combination with GA3 (0.1 and 0.15 mgl-1) significantly improved the root length and shoot length of rapeseed MDEs compared to separate use of smoke-extract solutions. Use of filter paper saturated with aqueous smoke extract (1:250) on top of the B5 regeneration medium was the best smoke treatment method improving the plantlet regeneration percentage, root length and shoot length of rapeseed MDEs compared to other treatment methods. The conversion frequency of rapeseed MDEs pretreated with smoke extract dilution of 1:500 was improved up to 50% compared with the control MDEs (26.67%), whereas the use of smoke extract (1:100) in B5 regeneration medium enhanced the conversion frequency of these MDEs up to 62% compared with the control cultures (26.67%).

In many forage legumes, hard seed coat is the main problem impeding the germination by preventing water and gases transport in seed. We evaluated the effects of mechanical scarification, chilling, different seedbeds (peat and sand) and their combination on the germination ratio and time of 9 naturally grown legume species belonging Lathyrus and Vicia genus. Control seeds showed very low germination ranging from 0% in V. narbonensis and V. sativa to 24% in L. annuus among to species. Mechanical scarification highly increased germination in all the species ranging from 27% in V. sativa to 96% in L. sphaericus. The highest germination of all the investigated species (ranging between 100 and 51%) was determined in the combination of mechanical scarification and sowing in peat treatments. Under this treatment, germination was improved greatly from 1% in control to 100% in V. bythinica while the germination of V. narbonensis increased from 0% in control to 51%. Any treatment which is highly promotes germination of one species generally accelerated the germination time of same species. The effect of treatments subjected to present study on germination ratio and time was generally, with exceptions higher for Lathyrus species compare to Vicia species.

In order to evaluate the informal wheat seed contamination with seed-borne diseases, two most important provinces (East Azarbaijan and Khorasan Razavi) for wheat production were selected in cold region of Iran in 2008-2009 crop seasons and ten different locations (city or village) were considered in each province and ten informal seed farmers were selected randomly. A seed sample (1 kg) was taken from planting source of each farmer. Different analysis including purity, germination and seed health (head blight, common bunt and loose smut disease) tests carried out on seed samples according to ISTA rules. Fusarium graminearum was identified as the main disease in provinces. Blotter test showed significant differences (P<0.05) among the towns but there was no meaningful difference between provinces. Washing test for T. caries showed significant difference between the two provinces (P<0.1) but there was no meaningful difference among towns in each province. Furthermore there was significant difference between and among provinces and towns with respect to T. leavis infection. Also the data showed clear dispersal of these two species (T. caries and T. leavis). Negative and high significant correlation was observed between U. tritici and germination. So the precision study of seed borne disease in different areas of the country for producing healthy seed is recommended.

The effects of drip irrigation and different cultivation methods on seed germination and growth of Puccinellia tenuiflora in saline-sodic soils were investigated in field experiments during 2008-2010 in the Songnen Plain, China. Drip irrigation was applied to waste saline-sodic P. tenuiflora grasslands for both flat and ridge cultivation methods. Drip irrigation affected the distributions of electrical conductivity of saturated-soil extract (ECe) and pH of the saline-sodic soil. After cropping under drip irrigation for two years, the ECe and pH had decreased greatly in the root zone on both the flat and ridge lands, and enabled P. tenuiflora seeds to germinate and grow rapidly. In addition, the plant height, number and length of spikes, coverage and aboveground biomass were all higher on the flat than on ridge land, but the differences of the two cultivation methods were not obvious. Compared to ridge planting, the flat planting method was more convenient, and flat cultivation and drip irrigation may be appropriate for restoration of saline-sodic grasslands.

High seed quality is a critical component for realising yield potential. For smallholder cowpea farmers in northern Nigeria the informal seed system is a major supplier of genetically high-quality seed, but the physiological quality of farmers’ produced seed remains unknown. The project “Promoting Sustainable Agriculture in Borno State” (PROSAB) trained and supported farmers in seed production in Borno State, Nigeria. We analysed the quality of farmers’ produced cowpea seed based on standard quality testing criteria, and evaluated its field emergence as a proxy for non-genetic seed quality. We carried out a survey among seed producing farmers about their production and storage practices, and tested seed quality of samples from these farmers, from seed companies and compared these to foundation seed. Field emergence of farmers’ produced seed was not significantly different from that of foundation seed (P=0.47) or seed company samples (P=0.12). Cowpea seed quality, however, was inadequate in both the formal and informal seed systems. Five out of six foundation seed samples, 79 out of 81 samples of farmers’ seed, and six out of six seed company samples failed to meet standards for foundation and certified seeds of the National Agriculture Seed Council (NASC), the seed industry regulatory agency in Nigeria. Multiple regression analyses predicting field emergence showed that projects like PROSAB can improve seed quality. Especially proper storage and reducing seed damage can increase field emergence significantly. Our findings suggest that it is worth to invest in improving the informal seed system of cowpea.