پديد آورندگان :
رضوانی مقدم پرویز نويسنده گروه زراعت و اصلاح نباتات، دانشكده كشاورزی، دانشگاه فردوسی مشهد Rezvani Moghaddam P , ثقه الاسلامی محمد جواد نويسنده گروه زراعت، واحد بیرجند، دانشگاه آزاد اسلامی، بیرجند Seghatoleslami M. J , موسوی غلامرضا نويسنده گروه زراعت، واحد بیرجند، دانشگاه آزاد اسلامی، بیرجند Mosavi Gh. R
چكيده لاتين :
<strong >Introduction </strong >
Purslane (Portulaca oleracea L.) is one-year and C4 plant of the family Portulacaceae. Purslane is a drought- and salt-tolerant plant, which contains high amounts of beneficial omega-3 fatty acids and antioxidant vitamins. Make it a prime candidate to form edible landscape in areas with dry conditions and salty soils, which are often present together where land is irrigated. Purslane seeds provide nutritional value, and have beneficial health effect on body specially in preventing cardiovascular, cancer and hypertension (high blood pressure) diseases, because it contains omega-3 and omega-6 fatty acids and other nutrients such as antioxidants, tocopherols and dietary fibre.
<strong >Materials and Methods </strong >
This study was conducted in the 2011 growing season at Agricultural Research Station of Islamic Azad University, Birjand (Latitude: 32°53 'N; Longitude: 59°13 'E and Elevation above sea level: 1480 m), Iran. Climate in this area is semi-dry to dry (annual rainfall is about 176 mm, maximum and minimum temperature are 39.1 and -17 degrees centigrade, respectively). The soil of the field was Sandy clay loam with pH 8.38 and with an EC of 2.74 m. mohs.cm-1. In this study, the effect of four sowing dates (4 April, 21 April, 5 May and 20 May) and three plant densities (5.5, 8.3 and 16.6 plants m-2) were investigated as main plot and sub plot, respectively in a split plot design based on randomized complete blocks with 3 replications. Each plot was 2.4m×6m with six planting rows. The space between rows, plots and replications was 0.4, 0.8 and 2 m, respectively. The field had been left fallow in the previous year. Sowing was done manually and was wet planting. Irrigation was employed with an interval of 4 days immediately after planting for uniform emergence until establishment of seedlings and after that continued weekly. To achieve the desired density, the seed was planted with high density, then the operation in two stages six and eight-leaf thinning, the density was obtained. According to the results of soil test, 100 kg/ha Triple superphosphate and 100 kg/ha soleplate potassium was applied to the soil before final disking. Nitrogen fertilizer was applied 300 kg/ha (as 1/3 at sowing, 1/3 at first harvest and 1/3 at second harvest) in the form of urea. Weed control was done manually in three stages. There was no specific pests and diseases during the growing season. In this study, we evaluated traits such as number of capsules per plant, number of seeds per capsule, 1000 seed weight, seed yield, biological yield, harvest index and forage yield. All statistical calculations were carried out by MSTATC software and the means of the studied traits were compared by Duncan’s Multiple Range Test at 5% probability level.
<strong >Results and Discussion </strong >
The results showed that delay in sowing date, reduced the number of capsules per plant, number of seeds per capsule, 1000 seed weight, grain yield and forage yield. For each 15-day delay in planting, seed yield reduced by 12.6%, 49.7% and 31.8% respectively. In planting 15 April, optimum environmental conditions such as light, temperature and longer growing period, resulted in hgher plant photosynthetic and thus biomass and grain yield increased. Effects of plant density on all measured traits (with the exception of 1000 seed weight) were significant. Increasing plant density decreased all measured traits with exception of number of capsules per plant and number of seeds per capsule. The planting density of 16.6 plants m-2 compared to 8.3 and 5.5 plants m-2, reduced the grain yield 55.6 and 67.4 % respectively. In the low densities, due to low leaf area, photosynthetic rate and biomass decreased and the seed yield was low. Interaction between sowing date and plant density on biological yield and dry matter yield were significant. Highest biological yield was of sowing date 15 April and plant density 16.6 plants m-2 and the lowest, in plant density of 5.5 plants m-2 in all sowing dates studied. Highest dry matter yield obtained from sowing date 15 April and plant density of 16.6 plants m-2 and the lowest, was for sowing date 21 April and plant density of 5.5 plants m-2.
<strong >Conclusions </strong >
Sowing date of 4 April and plant density of 16.6 plant m-2 can be recommended to obtain high seed and biomass yield of purslane.