Iranian Journal of Crop Sciences
Year:2004 | Volume:6 | Issue:3|Papers Count:9

The aim of this study was production of haploid plants, using microspore culture method, in to be used in rapeseed breeding programs. Donor plants (cv. Global) were grown at a day/night temperature of 15/10˚C (16/8 hours). After 90 days microspores were isolated from buds 2.5-3.5 mm containing microspores at late-uninuclate to early-binucluate stages and cultured in a modified medium (NLN-13). Samples were incubated at 30˚C and in darkness for 14 days then transferred to a shaker at 25˚C for 20 days. In this experiment, the effect of different microspore densities included of: 60000, 40000 and 20000 microspores per ml, was used to study the embryogenesis of microspores. Indeed, effect of embryo size (2-3, 3-4, 4-5, 5-6 and greater than 6 mm) on seedling germination properties like shoot formation, secondary embryogenesis and root formation were also studied. Results showed significant differences between various culture densities (p<0/01). The density of 60000 microspores produced 1031 embryos in each petri dish (containing 12/5 ml culture medium) and was the best density in this study. The size of embryo showed significant effects on shoot and root formation at 1% of probability level. The size of embryo also showed significant differences on secondary embryogenesis at 5%. Probably level in this expriment, it was observed that 73.33 % of embryos greater than 6 mm produced normal shoot had the best form of germination. In this study 43% of embryos were also regenerated.

To evaluate the effect of different weeds interference periods on shoot and root growth and harvest index of chickpea, an experiment was conducted at two environments using randomized compelete block design with four replications. Experiment environments were Tabriz and Kermanshah at first and second year, respectively. In each experiment, twelve treatments consisted of six initial weed-free periods (in which, plots were kept free of weeds for 0, 12, 24, 36, 48 and 60 days after crop emergence (DAE), and then weeds were allowed to grow until harvest) and six initial weed-infested periods (in which, weeds were allowed to grow for 0, 12, 24, 36, 48 and 60 DAE, after which the plots were kept free of weeds until harvest). The results indicated that, with increase of weed-infested and reduction of weed-free duration, the length and weight of chickpea shoots and roots significantly reduced as compared to control (weed free for all of the growing season). The reductions were more for roots than shoots. Consequently, shoot length: root length and shoot weight: root weight ratios increased. Moreover, reduction was more for weight of shoots and roots as compared to their length. Harvest index was also significantly decreased with increasing of weed-infested duration and decreasing of weed-free period. This reduction was 42.8% for full season weedy treatment as compared to control.

This experiment was carried out to compare the potential for forage production is 12 clover cultivars in Karaj in three cropping seasons. The experimental design was RCBD with three replications. The results showed  that the effects of years, cultivars, cuttings and the interaction of cutting * cultivars were significant for dry matter at 1% probability level. The comparison among different cuttings showed that the highest dry matter were obtained from the first cutting in 1999 and 2001  (2.14 and 2.85 t/ha) respectively, and from the second cutting in 2000 (2.68 t/ha ). Generally the first cutting had higher dry matter than other cuttings. Mean comparison for dry matter production, over season, of persian clover cultivars showed that the cultivar Aleshtar with  8.48 t/ha in  1999 and the cultivar Doochin-e-kordestan with 9.31 t/ha in 2001, and the cultivar Aleshtar with 8.53 t/ha had the highest dry matter among all cultivers. Significant difference was also observed in morphological characters among clover cultivars at 1% probability level. Overall, results showed that the Berseem clover for the plant height, the persian clover for the internode length and sub-branches number, and the Red clover for the leaf/stem ratio were superior. Regarding potential for forage production, Aleshtar, Simipilyosum and Tolidy-e-karaj cultivars could be recomended for Karaj region.

The present study was conducted to determine high yielding rapeseed cultivars adapted to different agro-climatic conditions. The 22 spring type rapeseed genotypes as well as a check cultivaer (Sarigol) were evaluated in a randomized complete block design with four replications in four locations for two cropping seasens (2000-02). Simple ANOVA of yield showed significant differences among the genotypes. In combined analysis of variance (based on 8 environments), the effects of locations and years were not-significant, but interaction effect of year x location was highly significant. Differences among genotypes were also significant, while the mean squares of genotype location and genotype * year interactions were not significant , however the mean squares of genotype * year * location interactions were significant. According to the Eberhart and Russell’s, mether genotype No. 21 (Hybrid Hyola401) with highest yield , coefficient of regression equal to unity and non- significant deviation from regression was the most stable genotype. Differences in grain yield of genotypes No.2 (S-2), No. 20 (Hyola308) and  No. 21 (Hyola401) were not significant, Therefore recognized as genotypes with average stability. Based on coefficient of variation (CVi), genotype no.3 (Cyclone) was one of the three stable genotypes followeing to Hyola 401 and S-2, coefficient of determination (R2) of these genotypes were  highly significant . Finally, based on simultaneous selection for yield and stability, the high yielding genotypes  No. 21 (Hyola401), No. 2 ( S-2) and  No. 20 (Hyola308) could be recominended Roz target enivaronments.

In order to investigate the effect of seed rate on yield and its components of dryland wheat genotypes a field experiment was conducted as factorial arrangement in a randomized complete block design (RCBD) with four replications during 1998-2001at Maragheh Agricultural Research Station, Dryland Agriculture Research Institute (DARI). The treatments included four levels of seed rates (250, 300, 350 and 400 seeds per squre meter) and three new dryland wheat genotypes (V1= Azar 2, V2 = Sbn//Trm/K253 and V3 = Sbn/1-27-56-4).Grain yield, plant height, kernel number per spike, spike number per squre meter, spike lenght and 1000KW determined from the middle of each plot. The results showed that seed rate of 300 seed per squre meter and Azar 2 (V1) had the greatest grain yield (1250kg.ha-1) and maximum water productivity (5.31 kg.mm-1), and can be recommend for areas of similar conditions.

Interaction effects of phosphorus and zinc fertilizer applications on nutrient concentrations and grain yield in cv. Sardari were studied under dryland conditions. In order to do this study, experiments were conducted with 4 phosphorus levels (0, 50, 100 and 150 kg P2O5.ha-1) and 4 zinc levels (0, 10, 20 and 30 kg Zn.ha-1) in using factorial arrangement in Rondomized Complete Block Design with 3 replications for 3 cropping seasons (1995-1998) in Dryland Agricultural Research Institute Station, maragheh, Iran. The results showed that phosphorus application did not significantly increase 1000-kernel weight, wheat grain and straw yield. However, phosphorus application increased concentrations of P, Fe, Mn, Cu and B in flag leaf, but decreased Zn concentration. Znic application increased grain and straw yields. Zinc application also increased N and K concentrations in flag leaf but decreased P, Fe and Mn concentrations. Phosphorous and Zine fertilizer applications increased grain and straw yields, but dercreased K, Fe, Mn and B concentrations in flag leaf of Path analysis showed that grain yield correlated with Mn concentration in flag leaf and influenced in variation concentration of other nutrients. It could be concluded that phosphorus and zinc fertilizer applications influance grain yield and nutrient concentrations in plant. If phosphorus and zinc fertilizers are applied together, Mn fertilizer is required for nutrient balance to optimize grain yield.

Crop residues are vital organic resources and their extensive use in management for sustainable agriculture is widely recommended. Nitrogen is an important element for wheat production. This study examined the effects of different wheat straw and nitrogen fertilizer levels on yield, N uptake and soil organic matter. The experiment was conducted in two years under Ahvaz climatic conditions. Treatments were laid out in a split plot, randomized complete block design with four replications. Main plot treatments were growing a plant (as green manure) with all wheat straw (a1, a5), growing a plant (as green manure) with previous crop residual after removing of percentage straw from the field (a2, a7), mixed the whole straw with soil (a3), mixed wheat crop residues after taking out straw from the field (a4), burning the plant residue after harvested as traditional farming system (a6), and removing the whole residual of previous crop (a8). These preplanting operations were combined with three levels of chemical fertilizers; i.e. b1 for high grain yield potential, b2 for medium, and b3 for commonly harvested grain yield. Combined analysis of variance of two years showed that the effect of plant residue on soil organic matter was significant. Residue burned with 0.632 percent the lowest and the highest was 0.798 for a1. Main effect and interaction of treatments were not  significant on soil nitrogen before top dressing on every year. Grain yields of different combination on combined analysis of variance was not significant. The higher yields were obtained from following combinations: a1b1، a3b2، a4b1، a4b2 ، a6b2 ،a7b1 and a7b2  with 5.215, 4.868, 5.138, 5.06, 4.895, 5.719 and 5.011 kg/ ha yield respectively.

To determine the effect of sowing dates (22 Oct., 5 Nov., 21 Nov. and 5 Dec.) on the green pod and dry seed yield of faba bean (Vicia faba), field experiments were conducted using RCB design with four replications for three cropping seasons (1995-1998) at Hashem Abad Research Station in Golestan Province. Result, of combined analysis of variance showed that 22 Oct. and 21 Nov. produced higher green pod yield of 20440 and 20540 kg/ha, respectively. In cotton growing area of Golestan it is important to plant cotton after harvesting of faba bean green pods, as soon as possible, for using soil moisture to prepare bed for cotton seed. There was no significant difference between yield of 22 Oct. and other dates of sowing. It is therefore, suggested to plant faba bean as early as 22 Oct. for green pod. The results of combine analysis of variance on dry seed yield also showed that the highest seed yield (3861 kg/ha) were produced from 21 Nov. sowing date. Therefore, faba bean may be planted on 21 Nov. for dry seed production.