JOURNAL OF CROP PRODUCTION RESEARCH (ENVIRONMENTAL STRESSES IN PLANT SCIENCES)
Year:2011 | Volume:3 | Issue:3|Papers Count:8

In order to study the yield and yield components of grain sorghum (Sorghum bicolor L. Moench) an experiment was conducted in 2008 at the research field of Seed and Plant Improvement Research Institute at Karaj (Alborz Province). Ten sorghum genotypes (KGS5, KGS11, KGS12, KGS15, KGS23, KGS24, KGS25, KGS31, ICSV274 and UT378B) were studied in a randomized complete block design with four replications. Different traits including grain and biological yields, harvest index (HI), the number of panicles/m2, the number of grains/panicle, 1000 grain weight, the number of spikelets/panicle and the number of grains/spiklet were studied. The results indicated that the highest grain and biological yields (9895.8 and 51023 kg.ha-1) belonged to genotypes KGS5 and KGS23, respectively, while KGS31 and KGS11 genotypes had the lowest grain and biological yields (6348.2 and 35659 kg ha-1). Harvest index (HI) significantly differed between genotypes so that KGS5 and KGS31 genotypes had the highest and lowest HI (24.54% and 16.9%), respectively. With respect to the yield components, genotypes UT378B and ICSV274 had the highest number of grains/panicle and 1000 grain weight, Alternatively. The weakest genotypes with regard to these characteristics were KGS24 and KGS12. As observed, high grain yield of KGS5 genotype did not coincide with high yield components but its high HI could compensate for moderately low yield components. Overall, it could be concluded that the most important and effective trait in achieving high grain yield in sorghum is high HI, so that sorghum grain yield could be still further increased by increasing this trait. The KGS5 genotype was also selected as an ideotype for sorghum due to its superiority in case of grain yield, HI, the number of grains/panicle and 1000 grain weight.

To investigate the impact of water deficiency on vegetative characteristics and grain yield of oil seed sunflower cultivars an experiment was done during the years of 2004-2005 in the Agricultural Research Station of Khoy. The experiment carried out in split plot on the basis of randomized complete block design with four alterations. The irrigation levels, as the main factor were in 6 levels including: 70 –70 –70, 90 –90 –70, 110 –110 –110, 90–70 –90, 110–70 –110, and 90 –90 –110 mm evaporation from class A pan, from seedlings establishment up to the appearance of head; followed by turning into yellow and finally to the physiological rippening and the cultivar as the secondary factor including: Hisun 33 , Record and Armaverski were chosen. The results of the experiment showed that with increase in the distance between irrigations (110–110–110 and 90–90–110 mm) plant height, leaf area index, stem and capitulum diameter, grain and biological yield were reduced. The highest grain and biological yield (5125 and 13278 kg/hectare) belonged to 70–70–70 mm treatment which wasnot showed any significant with 90–70–90 mm treatment. Under severe water stress (110–110–110 mm) the least amount of grain and biological yield were abtained. Concerning with the studied traits Record and Hisun33 cultivars were better than Armaverski. The general results of this research showed that the sowing of oil cultivars of Record and Hisun33 with the irrigation distances of 90 mm evaporation in the beginning and ending of the growth season are suitable for Khoy region. But because of the sensitivity of sunflower to water deficiency, the time of irrigation must be regulated on the basis of 70 mm evaporation from the appearance of the head till turning into yellow.

Due to identify the winter wheat varieties tolerant to end season drought stress using stress tolerance indices, a field experiment was performed during 1388-89 crop year in the basis randomized complete block design with four replications at the Agricultural Research Station, Islamic Azad University Karaj Branch. In this study, 10 wheat cultivars at two irrigation levels including, Normal irrigation and cut off irrigation from flowering stage to end of growth period were studied. Based on results of mean comparisons, drought stress after flowering stage reduceded grain yield and its components in all genotypes compared with normal irrigation conditions. Highest grain yield in full irrigation conditions, related to Pishgam, Sayson and Gaspard 8074, 8024 and 7653 kg ha, respectively, and the lowest belonged to Alamut. Also in stop irrigation conditions the highest yields observed in Sayson, Pishgam and Kaskozhen 5738, 5703 and 5479 kg/ha, respectively, and Alamut, toos and back cross showed the lowest performance. For cultivars tolerance assessment to droght stress, Sensitivity to Stress Index (SSI), Harmonic mean (HARM), Tolerance Index (TOL), Mean efficiency (MP), Stress tolerance Index (STI) and Geometric Mean Efficiency (GMP) was used. Examining selected indicators for drought tolerance indicated that Sayson, Pishgam and Kaskozhen varieties were introduced as drought tolerant varieties in end season drought stress and STI, MP, GMP and HARM were the most suitable indices for applying in wheat breading programs. The mentioned indices have the most correlation with grain yield at normal and drought stress condition.

In order to study the effect of seed germinability on cotton commercial cultivars field emergence, an experiment was conducted in 2008 in Seed and Plant Certification and Registration Research Institute (SPCRI) research field. Therefore, Mehr, Varamin, Sahel and Bakhtegan cotton cultivars seeds had 70%, 80% and 90% germination which produced in 2007, planted as factorial 4´3 (4 cultivar´3 germinability) based on completely randomized block design in four replication. Then primary and final seedling emergence percent, mean emergence time, rate of field emergence and commulative emergence rate, field emergence index, seedling vigour index determined. Data analysis showed that studied cultivars over standard germinability seeds studied cultivars had better studied indices. Also Varamin cultivar except for seedling field emergence rate had better than other studied cultivars. Therefore with due attention to cotton high seed use rate because unreliability of farmers to enough seedling field emergence and establishment and in order to seed consumption decrease, totally based on this experiment results over standard germinability seeds planting was recommended.

In order to evaluation of spring rapeseed cultivars reaction to terminal drought stress, an experiment was carried out in a split plot design based on RCBD with four replications for two years (2006-2008) at the research field of Seed and Plant Improvement Institute in Karaj. In this experiment, irrigation treatments in two levels as main plot such as normal irrigation (irrigation after 80 mm evaporation from evaporation pan) and water deficit stress as no irrigation from stem elongation to end of growth and varieties as sub plots in 20 levels ( Sarigol, Goliath, Heros, Comet, Amica, SW5001, Cracker Jack, Eagle, Wild Cat, SW Hot Shot, Ogla, 19-H, Hyola 401, Hyola 60, RGS006, Hyola 420, RGS003, Option 500, Hyola 308 and Quantum ). The results indicated that water deficit stress decreased plant height, branch per plant, pods per plant, grain per pod, 1000 grain weight, biologic yield, grain yield, seed oil content and oil yield, but there was not significant effect on harvest index. Under normal irrigation, Hyola 401 with high grain in pod and 1000 grain weight had the highest grain yield whereas, in water deficit stress conditions, RGS003 with greatest grains in pod and 1000 grain weight produced the maximum grain yield and it had the highest stress tolerance index (STI) in comparison with others varieties. Also, Quantum variety with the lowest grain yield under normal irrigation (3492 kg.ha-1), water deficit stress (2948 kg.ha-1) and small STI had the more susceptive to water deficit.

In order to study the effect of the time and concentration of methanol spraying on the growth and yield of mungbean (Vigna radiata L.), a factorial experiment in the basis of completely random blocks was done with three replications in Agricultural research farm of the Islamic Azad University, Rasht branch in the north of Iran during 2009. The concentration factor of methanol foliar application was in four levels, control (without spraying), 10, 20 and 30 volumetric percentages of methanol; while the time of methanol spraying considered in three levels: in the morning (8:00-10:00 a.m.), at noon (13:00-15:00 p.m.) and in the afternoon (17:00-19:00 p.m.). The Results showed that there was a significant difference between methanol concentrations for seeds numbers per pod, harvest index and seed yield. In this case the largest seeds number per pod (13.11 seeds) and harvest index (38.22%) observed in 30% methanol consumption, while the highest seed yield conducted in 20% methanol foliar application(55.97 g/m2). Effect of spraying time was significant on seed yield and harvest index, the highest average amount of seed yield (55.52 g/m2) and harvest index (36.69%) gained after spraying in the afternoon. The interaction effect of two factors on none of the studied traits was not significant.

In order to study the effect of different planting patterns on yield and morphological characters of 4 cotton varietes an experiment was conducted as factorial in the basis completely randomized blocks desighn with 3 replication in spring 2010 at the Agricultural Research Center and Natural Resources of Yazd. Planting patterns [square(40×40 cm), rhombus (40x40 cm) and rectangle (40x80 cm)] and cultivars (Varamin, Mehr, Sindoz and B512) were the experimental factors. In this research number of leaf, plant height, number of bolls, number of closed bolls, first pick yield percent, second pick yield percent, first pick yield, second pick yield and total yield were measured. The results showed that square pattern produced maximum yield which indicate distribution of plants in the square pattern is more uniform and reduce competition of plants for light and cause higher yield. The results also revealed that number of leaves and plant height of Mehr was more than the other varieties, but Sindoz variety produced highest yield (3907 kg/ha). The highest number of bolls was produced by B512 variety but the entire bolls didn't altered to open bolls. The highest yield (5642 kg/ha) was obtained by using square pattern and Varamin variety.

In order to survey of chlorophyll content and some agronomical traits of maize hybrids under water deficit stress, a field experimental was carried out as split plots based on randomized complete blocks design with three replicates in the research station of Islamic Azad University, Arak Branch, Iran in 2009. Experimental factors were irrigation in three levels: %100 (control) , 75% and 50% crop water requirement as main plot and maize hybrids including SC500, SC524, SC700, SC704 and DSC370 as sub plots. The results showed that drought stress was decreased the stem diameter, length of ear leaf, leaf chlorophyll content and grain yield. The highest chlorophyll content was obtained from SC524 hybrid. The maximum grain yield was obtained from early and mid maturity hybrids. Interaction effect of treatment showed that the highest grain yield (8624.22 Kg. ha-1) was obtained from SC524 and %100 crop water requirement while the lowest grain yield (4072.32 Kg. ha-1) belonged to SC700+%50 crop water requirement. In general, The results showed that in optimum and drought stress conditions, grain yield of early and mid maturity hybrids was more than late maturity ones.