SEED AND PLANT PRODUCTION JOURNAL
Year:2013 | Volume:29-2 | Issue:1|Papers Count:11

One of the major problem in apricot production is serious damages of flower buds and developing fruits due to late spring frost. Selection of cultivars with lower yield fluctuation in spring frost prone areas is important. Therefore, the objective of this research was to evaluate the effects of late spring frost on fruit yield, phenological and physiological traits of 26 apricot cultivars in orchard conditions. The experiment was carried out in randomized complete block design with three replications in Garizeh agricultural reseach station, Sanandaj, Iran, in 2007 and 2008 growing seasons. Spring frost damage was observed as blackening of flower pistil and young fruit seed. Results showed significant (p<0.01) differences among cultivars in all measured traits. “Dorosht-e-Malayer” cultivar had the earliest flowering time and the longest flowering period as compared with other cultivars. “Ghermez-e-Shahroud” cultivar showed the highest frost injury. Although “Jahangiri” showed the highest fruitset (%22.88), but “Tilton” had the highest fruit yield (22.66 kg tree-1). “Ghamishlu” cultivar had the latest flowering time, the lowest fruitset (4.87%) and fruit yield (2.67 kg tree-1). Results also indicated that the range of flowering date among apricot cultivars was narrow (7 days), and late flowering cultivars had lower fruit yield. Fruit set showed significantly (p<0.01) positive correlation with yield, proline and K+ contents. Cultivars with higher proline and K+ contents showed higher fruit sets and lower yield fluctuations under spring frost conditions, perhaps due to higher cold hardiness. “Tilton”, “Royal”, “Dorosht-e-Malayer”, “Ghorban-e-Malayer”, “Hashtalui”, “Khorramta 1” and “Khorramta 2” apricot cultivars are suitable for spring frosts prone areas.

To study the effect of plant growth promoter bacteria (PGPB) (Azospirillum spp.) on yield and yield components, dry matter and harvest index of two canola (Brassica napus L.) genotypes, an experiment was conducted at Agricultural Research Station of Gorgan during 2009-10 growing season. The experiment was arranged as factorial in randomized complete block design with three replications. Eight fertilizer treatments (1-Control, without fertilizer and bacteria, 2-Fertilizer recommendation with soil test, 3-50% of fertilizer recommendation, 4-AZ1 bacterium, 5-AZ10 bacterium, 6-50% fertilizer recommendation +AZ1 bacterium, 7- 50% fertilizer recommendation +AZ10 bacterium, and 8- 50% fertilizer recommendation +AZ1 and AZ10 bacteria), and 2 canola genotypes (Hyola401 and L6) were included in factorial arrangement. Results showed that the effect of fertilizer treatments was not significant on pod number plant-1 and seed number pod-1, However, it was significant on seed number m-2, 1000-seed weight, seed yield, aboveground dry matter at physiological maturity and havest index. The application of bacteria had a positive role to increase 1000-seed weight of canola genotypes. Fertilizer recommendation with soil test treatment had the highest seed yield (2892 kg ha-1). There was no significant difference between fertilizer recommendation with soil test and 50% fertilizer recommendation +AZ1 bacterium, and 50% fertilizer recommendation +AZ1 and AZ10 bacteria which showed the positive effect of AZ1 bacteria on seed yield of canola. Fertilizer recommendation with soil test had the highest aboveground dry matter at physiological maturity (9140 kg ha-1). On the other hand 50% fertilizer recommendation +AZ1 bacterium had the highest harvest index (31.9%). Seed yield and harvest index of L6 was significantly higher than Hyola401. The mean seed yield of Hyola401 hybrid and L6 was 2258 and 2504 kg ha-1, respectively. The results of this study showed that AZ1 bacterium had positive effect on increasing canola seed yield.

Modern agriculture often needs exact information about occurrence of crop phenological development stages that have many applications. Data from sowing date trials conducted in the Kaboutarabad Agricultural Research Station, Isfahan during 2003-2009 were used to develop models for estimating phenological development stages of safflower cv. Goldasht. To estimate duration of each phenological development stage, the period of each stage were used as the dependent variable and various temperature variables, day length and combination of these variables as the independent variable in a step-wise regression analysis. A step of regression analysis was considered appropriate, when the highest R2 was accompanied by the significant (p£0.05) regression coefficient and partial R2. The number of days from sowing to emergence, emergence to the commencement of heading, emergence to flowering, emergence to maturity and flowering to maturity were affected by sowing dates. Phenological development stages reduced as temperature increased. Day length had the highest effect on emergence to the commencement of heading and emergence to flowering periods and these periods reduced as day length increased. Tmean and T3max variables were entered in the regression model and explained about 89% of variation of duration of sowing to emergence. Duration of emergence to the commencement of heading was explained by DL×Tmax and DL2×T2max with accuracy of %88. DL×Tmax was entered in the regression model and explained about %95 of variation of duration from emergence to flowering. DL×Tmax and T2mean explained the highest variance (85%) of duration from emergence to maturity. Tmin was the only variable entered in the regression model and explained about 58% of variation of duration from flowering to maturity.

To assess the response of differen wheat genotypes to delayed sowing field experiments were conducted in Khorramabad research station during 2008-2010 growing seasons. Two sowing dates (Nov.10 and Dec.11) as main plots and 16 wheat genotypes as sub-plots were arranged as split plot in randomized complete block design with three replications. Results showed that effect of year, year×sowing date and year×genotype was significant on some characteristics, but the effect of sowing date and genotype was significant for most of traits. Delayed sowing caused reduction of grain m-2, spike m-2, plant height, days to heading and days to maturity and grain yield. Deleyed sowing reduced grain yield about 29 kg ha-1d-1. Durum wheat cv. Dena and bread wheat lines S-83-3, S-83-4 and S-84-14 with average grain yeild of 6148, 6412, 6679 and 6036 kg ha-1, respectively, were suitable for delayed and optimum sowing dates. There was significant positive correlation between grain yield and some of the traits. The highest correlation coefficeint was observed between grain yield and grain m-2 (r=0.70**). Although there was no significant difference between the average grain yield of durum and bread wheat, genotypes however, changes (%) in grain yield of durum wheat was less than bread wheat in delayed sowing date.

This study was carried out as factorial arrangement in randomized complete block design with three replications in two years (2006 and 2007) in Jiroft and Kahnouj Agricultural Research Center, Jiroft, Iran. The first factor was eliminating of irrigation at different growth stages at five levels 1- eliminating irrigation from 4-6 leaf stage to prior to flowering, 2- eliminating irrigation from 4-6 leaf stage to full flowering, 3- eliminating irrigation from flowering to the end of the growing season, 4- eliminating irrigation from 4-6 leaf stage to prior to flowering and from flowering until the end of the growing season, 5- Full irrigation based on 100 mm evaporation from class A pan (control), and the second factor was sesame genotypes, local Jiroft variety and JL-13 line. Branch plant-1, capsule plant-1, seed capsule-1, 1000 seed weight, seed oil content, plant height, biological yield, seed yield and harvest index were measured. Results showed that eliminating of irrigation at different growth stages significantly affected seed yield, capsule plant-1 and seed capsule-1, 1000 grain weight, branch plant-1, plant height, biological yield and harvest index. Eliminating of irrigation at different growth stages significantly reduced grain yield, yield components, branch plant-1, plant height, biological yield and harvest index. The least reduction rate in seed yield, yield components, lateral branches, plant height, biological yield and harvest index was recorded in eliminating of irrigation from 4-6 leaf stage to prior to flowering, and it had the highest seed yield following the control. Eliminating of irrigation from 4-6 leaf stage to prior to flowering and from flowering to the end of growing season had a considerable impact on seed yield and yield components and had the lowest seed yield. JL-13 line produced higher seed yield under stress and non-stress conditions.

To evaluate and compare the quantitative and quality of forage in vetch and grasspea intercropping with annual grasses under rainfed conditions of Markazi Province, an experiment was carried out in 2008-2009 and 2009-2010 growing seasons in dryland agriculture field station, Agriculture and Natural Resources Research Center of Markazi Province, Frahan, Tafresh, Iran. Randomized complete block design with three replications was used. Treatments included pure culture vetch (Vicia Panonica), grasspea (Lathyrus Sativus) with a density of 250 seeds m-2 and annual grasses included triticale and annual lolium (Lolium multiflorium) with a seed density of 400 seed m-2 and the ratios of various intercropping; legumes 75%+grass 25%, legumes 50%+grass 50%, legumes 25%+grass 75%. Intercropping vetch 50%+triticale 50%, grasspea 25%+triticale 75%, grasspea 50%+triticale 50%, vetch 25%+triticale 75%, vetch 75%+triticale 25% and grasspea 75%+triticale 25% with 5615, 5520, 5461, 5130, 4718 and 4693 kg ha-1 had higher dry forage yield, respectively. Grasspea 25%+triticale 75% with 805 kg ha-1 had the highest protein yield. Land equivalent ratio (LER) of the intercropping treatments were larger than the unit. The intercropping treatments grasspea 50%+triticale 50% and grasspea 25%+triticale 75% for dry forage with 1.43 and 1.42, and for protein yield grasspea 25%+triticale 75% and grasspea 50% + triticale 50% with 1.66 and 1.47 had higher LER, respectively. It is concluded that with intercropping vetch 50%+triticale 50%, grasspea 50%+triticale 50% and grasspea 25%+triticale 75% considerable forage can be produced. These intercroppings are suitable alternative for fallow practices following wheat in drylands in Farahan region of Markazi Province in Iran.

To study response of cotton (Gossypium hirsutum L.) cultivars to topping and pix as a plant growth regulator an experiment was conducted in Parsabad, Moghan region of Iran with four cultivars included Sahel, Varamin, Bakhteghan and Mehr and topping at 30 days after flowering (DAF), pix spraying at 15 and 30 DAF, and a treatment with neither pix nor topping as control. Results indicated that Sahel had good response to pix spraying at 30 DAF and could increase lint yield up to 210 kg ha-1 when compared to the control. For Sahel cultivar that was sprayed and topped at 30 DAF, cotton plants matured earlier, but other treatments especially control plots matured later. Pix sprayings and topping had no-significant effect on plant height of Varamin, and there was not significant difference among treatments for earliness. Bakhteghan sprayed with pix at 30 DAF was earlier by 78%. Response of Mehr to spraying was better than topping, and after treatment its yield improved (1015 kg ha-1) as compared to the control. Mehr in topping at 30 DAF with 78% earliness was earlier than other cultivars. It is concluded that cotton stem topping of 10-15 cm and pix spraying may decrease plant height and increase earliness and yield of Sahel, Bakhteghan and Mehr cotton cultivars.

To study the effect of salt stress on chlorophyll fluorescence and seed yield of sunflower two experiments were conducted in greenhouse and field conditions in Shahid Bahonar University, Kerman, Iran, in 2010. Seven sunflower cultivars including; Zaria, Bilizar, Armavirosky, Euroflou, Hysun 33, Farrokh and Progress, and four levels of salt stress; 2, 4, 6 and 8 ds m-1, were studied as factorial arrangement in randomized complete block design with three replications in greenhouse and as split-plot arrangement in randomized block design in field conditions. Results showed that initial (F0) and maximum (Fm) fluorescence as well as quantum yield were significantly affected by salt stress. Ion leakage, relative water content and seed yield were also affected by salt stress. Increasing salt stress level decreased all abovementioned attributes except F0, Fm and ion leakage. Variety×salt stress interaction effect was significsnt on all of measured characteristics except grain yield and relative water content. The highest grain yield (2736.9 kg ha-1) was obtained from cv. Progress.

Walnuts orchards in Iran are not uniform due to sexual propagation. Asexual propagation including minigrafting will lead to uniform orchards and nut production. To study the trend of grafting union formation in walnut some microscopic slides were prepared in different time after ‘Serr’ cultivar was minigrafted on seedlings. Different stages of grafting process including callus formation and development, necrotic layers deterioration, cambium differentiation and vascular tissues formation in samples were evaluated in 3, 7, 10 weeks; and 6 and 12 months after minigrafting. Results indicated that successful minigraft was observed after 12 months in winter minigrafted seedlings.

Production of haploid plants is an efficiant method in plant breeding programs, genetics and cytogenetics studies. Effects of cultivar, medium and plant growth regulators were investigated on anther culture of strawberry. This study was carried out using two commercial cultivars of satrawberry (Selva and Paros), three medium (MS, H1 and N6) and different concentrations of IAA and BAP as factorial arrangement in completely randomized design. Androgenic anthers (%), embryogenesis (%) and callogenesis (%) were determinded and recorded after 30 days. Results showed significant differences among treatments for studied traits. In the Selva cultivar, the interaction effects of the H1 medium and hormone treatments including T3 (2 mg l-1 IAA + 1 mg l-1 BAP), T2 (1 mg l-1 IAA+2 mg l-1 BAP) and T1 (1 mg l-1 IAA+1 mg l-1 BAP) showed the highest androgenic anthers (67.8%, 59.6% and 54.3%, respectively). In the Paros cultivar, the interaction effect of H1 medium×hormone treatments including T5 (3 mg l-1 IAA+ 2 mg l-1 BAP) and T3 (2 mg l-1 IAA+1 mg l-1 BAP) showed the highest androgenic anthers (70.5% and 67.7%, respectively). Interaction of T3×H1 medium produced the highest embryogenesis in both cultivars (Selva 37.8% and Paros 42.8%). This treatment was determined as suitable treatment for anther culture in both cultivars.

Haploidy method through androgensis is highly important in breeding of many plants. However, this method has not been successful in rose breeding, so far. In this research the responses of two rose species (Rosa damascena Mill. and Rosa hybrida) to anther culture were investigated by using some thermal and chemical pre-treatments. Results showed that the anthers cultured in early to mid-uninucleate stages produced a favorable callogenesis. The heat and heat-manitol pre-treatments caused cell death. The low temperature pre-treatment (4oC) for three days showed the best anther callogenesis among all studied treatments. The application of heat and cold pre-treatments after anther culture in H1 medium for 4 days significantly improved the callogensis.