فصلنامه اکوفیزیولوژی گیاهان زراعی
پیاپی 17 (بهار 1390)

To study the effect of drought stress and N fertilizer application on biological yield, grain yield and yield component of three wheat cultivars, a field experiment was conducted in 2006-2007 at Shushter region in Iran. The experiment was a factorial based on completely randomized block design with replications. Treatments were wheat cultivars (Chamran, Showa and Falat), N fertilizer in two levels (50 and 150 kg/ha) and levels of drought stress (without stress, and stress at grain filling). Chamran and Falat were soft bread wheat type and Showa was durum. Results indicated that under drought stress Chamran had the higher grain yield (5584 kg/ha) as compared to Showa (5332 kg/ha) and Falat (4821 kg/ha).The high level of N increased grain yield by 45% against low level N application. Response of Chamran to N fertiliser was more than that of Showa and Falat respectively. Spike number, grain number per spike and 1000 grain weight affected grain yield.

To study the effect of drought stress and N fertilizer application on biological yield¡ grain yield and yield component of three wheat cultivars¡ a field experiment was conducted in 2006-2007 at Shushter region in Iran. The experiment was a factorial based on completely randomized block design with replications. Treatments were wheat cultivars (Chamran¡ Showa and Falat)¡ N fertilizer in two levels (50 and 150 kg/ha) and levels of drought stress (without stress¡ and stress at grain filling). Chamran and Falat were soft bread wheat type and Showa was durum. Results indicated that under drought stress Chamran had the higher grain yield (5584 kg/ha) as compared to Showa (5332 kg/ha) and Falat (4821 kg/ha).The high level of N increased grain yield by 45% against low level N application. Response of Chamran to N fertiliser was more than that of Showa and Falat respectively. Spike number¡ grain number per spike and 1000 grain weight affected grain yield.

This study was carried out during two years (2009 and 2010) at the Agriculture and Natural Resources Research Station of Ardabil, Iran. In this study, 12 early growing (Marfona, Sinora, Fontane, Oshina and Natasha), moderately late growing (Satina, Markies and Arcona) and late growing (Luta, Agria, Savalan and Caesar) potato cultivars were arranged in randomized complete block design with three replicates in two separate experiments (spring planting and planting after harvesting barley). Analysis of variance of traits measured showed that three were significant difference between planting types, among cultivars and their interaction in both total and marketable tuber yields, tuber number and weight per plant; interaction between year×planting types, cultivars× planting types, year×cultivar and year×cultivar× planting type, average tubers size and among cultivars for plant height and main stem number per plant. Luta, Markies and Fontane cultivars had high total and marketable tuber yields and tuber weight per plant in spring planting, Arcona, Markies, Marfona and Luta cultivars in after barley harvest planting during 2009, Agria, Luta, Savalan and Caesar cultivars in spring planting and Luta, Savalan and Agria cultivars in after barley harvest planting during 2010. Relationship between total tuber yield with marketable tuber yield, tuber number and weight per plant and tuber size average were significant and positive. Tuber weight per plant had the most direct positive effect on the total tuber yield. It was also found that Savalan, Luta, Satina, Markies and Fontane (late and moderately late growing types) as high yielder and stable cultivars; Agria (moderately late growing) were to be as high yielder but unstable cultivars; Caesar (late growing type) as low yield but stable cultivar and Sinora, Oshina, Arcona, Natasha and Marfona as low yielder but unstable cultivars.

In this research effect of drought (water deficit) stress and manure on yield and some of the morphological characters of dragonhead was studied. In this study a strip plot pot experiment based on randomized complete block design (RCBD) was conducted in greenhouse with 15 treatments and 3 replication, in the Islamic Azad University Jiroft Branch in Iran during 2009. Three levels of water stress at 75% Fc (least stress), 50% Fc (moderate stress) and 25% Fc (severe stress) were considered as vertical factor and five manure levels (0 – 10 – 20 – 30 – 40 t/ha) were considered as horizontal factor. Total fresh and dry herb yield, plant height, number of stem, internode length, dry leaf and dry stem weights were measured. The results showed that the effect of water deficit stress on all morphological characters, except inter node length and stem number, were significant (= %5). The effect of manure on all morphological characters, except inter node length, were significant (= %5, = %1). Fresh and dry weights of herb, number of stem, plant height, dry leaf and stem weights decreased by increasing water stress. Water stress, significantly reduced on herb yield from 4868.27 kg/ha to 3348.00. Maximum dry herb yield with 4956kg/ha was due to 75% Fc (least stress) with manure treatment of 40 t/ha. Results of this study showed that by increasing manure level dry herb yield was increased. A significant positively correlation between dry herb yield and fresh herb (r = 0.969), number of stem (r = 0.849), plant height (r = 0.684), dry leaf (r = 0.969), dry stem (r = 0.974) were observed.

In order to investigate the effects of different weed control methods and moisture regimes on safflower (Carthamus tinctorius), a field split plot experiment based on randomized complete block design with 4 replications was conducted in Takestan Iran, during growing seasons of 2007-8. Three irrigations regimes (normal irrigation, restricted irrigation at stem elongation and restricted irrigation at flowering stage) were assigned to the main plots and nine chemical weed control method (complete hand weeding, treflan with 2 L/ha as pre plant herbicide, sonalan with 3 L/ha ad pre plant herbicide, estomp with 3 L/ha as pre plant herbicide, gallant super with 0/75 L/ha as post emergence herbicide, treflan with 2 L/ha as pre plant herbicide gallant super with 0/75 L/ha as post emergence herbicide, sonalan with 3 L/ha as pre plant herbicide gallant super with 0/75 L/ha as post emergence herbicide estomp with 3 L/ha as pre plant herbicide gallant super with 0/75 L/ha as post emergence herbicide and without hand weeding) to sub- plots. At the end of growing period traits like number of head per plant, number of seed per head, 1000 grain weight, percent of seed oil, yield of seed oil and grain yield were measured. Results indicated that treflan gallant super treatment in restricted irrigation at stem elongation stage had the lowest dry weight of weeds. In this study maximum grain yield (2927 Kg/ha) was achieved from hand weeding usual irrigation treatments. In general treflan gallant super treatment was the most effective treatment on safflower yield and weed control.

To evaluate grain yield and some agronomic traits of tow corn varieties as a second crop under drought stress and application of cycocel an experiment was conducted at Agricultural Research Station of Jahad-Keshavarsi of Khoy during summer growing season of 2005. Experimental design was a split-split plot based on RCBD with four replications. The factors consisted of irrigation as the main factor with three levels (irrigation after 70±5, 100±5 and 130±5 mm evaporation from class A pan), varieties 260 and 301 of corn as subfactor and application of different rates of cycocel (with and without application) as sub-subfactor. Results showed that drought stress reduced plant height, stem diameter, number of leaves and the leaf area index, biological yield and grain yield. Application of cycocel increased the stem diameter, biological yield and grain yield as compared with not application of cycocel. Generally, It can be concluded that irrigation after 70 mm evaporation and the application of cycocel can play major roles in increasing corn grain yield.

To investigate the effects of methanol on the yield and the yield components of chickpea, a factorial experiment was conducted in the form of a randomized complete block design during three replications at the Research Field of Islamic Azad University Karaj Branch in the year 2008. Aqueous solutions 0 (control), 5, 10, 15, 20 and 25% (v/v) of methanol containing 0.2% glycine as well as the two varieties of ILC 482 and Azad were factors of this study. After flowering, these solutions were sprayed over the plant heads three times in one-week intervals. The results of the ANOVA indicated that the effects of solutions on yield, 100 seed weight, biological yield and plant height were significant. Also, significant differences on all the characteristics under investigation except plant height and harvest index were evident between the two varieties (ILC 482 and Azad). Interactive effects on biological yield, yield and 100 seed weight were respectively significant at 1%, 1% and 5%, probability levels. According to the results, the Azad variety on 10% of methanol application produced the highest yield (2482.6 kg/ha) which is an increase of 126% as compared with the control. The ILC 482 variety on 20% of methanol application reached the second rank after Azad by 2425.5 kg/ha and it improved 50% in relation to the control. The mentioned treatments had similar biological yield conditions. Highest 100 seed weight increased 40% and 30% respectively as with by 36.98 gr. for ILC 482 on the 10% of methanol and 35.03 gr. for Azad on the 5% at methanol. The application of methanol, as a source of carbon, increases more carbon fixation by inhibiting the photorespiration. Therefore, it can be a positive factor in improving the photosynthesis and increasing the yield of chickpea.

In order to study the effect of plant density on seed yield and its components, a field experiment was conducted in 2007-2008 in Firouz-Abad province of Fars, Iran. The experiment was a split plot based on randomized completely block design with three replications. Main plots consisted of four corn varieties [late maturing 704 (V1), mid maturing 604 (V2), early maturing 370 (V3) and mid maturing 647 (V4)] and Sub plots four plant densities [6.5 plant/m-2 (D1), 7.5 plant/m-2 (D2), 8.5 plant/m-2 (D3) and 9.5 plant/m-2 (D4)]. The results showed that the highest grain yield, grain number per ear row, 1000-grains weight, biologic yield, plant height, stem diameter, ear length belonged to late maturing 704; and highest grain number per ear and harvest index were by mid maturing 647 and early maturing 370. Reaction of traits in hybrids to increase in density were different. For example, hybrid 704 produced highest yield so with 7.5 plant.m-2, hybrids 604 and 647 from 8.5 plant.m-2 and hybrid 370 with 9.5 plant.m-2. In all of the hybrids used increase in plant density from 6.5 to 9.5 plant.m-2. Grain number per ear row, grain number per ear, stem diameter and ear length descreased.