AGRICULTURAL RESEARCH
Year:2005 | Volume:4 | Issue:2|Papers Count:6

For finding the cumulative rainfall curves and determining the suitable pattern for time distribution of rainfall, cumulative rainfalls which determined by rain gauges were collected. The area chosen for this research is located in the south western of Zagros.Rain gauge data belongs to these stations having the different qualities. These data were tested for homogeneity by available methods and after elementary investigations on the quantity and quality of  these data and determining of confident data, a computer model for determination of rainfall cumulative curves developed. In this model the percentage of the cumulative rainfall height and the percentage of the cumulative rainfall time in all of the studying rainfall gauge stations were determined. These different cases were chosen in the above studies. In the first case, cumulative rainfall curves find out for each of rainstorm in all of the rain gauge stations of the studied area. In the second case, only one rain gauge station for all of the chosen rainstorm were studied. In the third case, the actions for all of the stations and for all of the rainstorm were studied on the same times. In each of the three above cases, the set of the curves resulted with the probabilities of 10 to 90 percentages which showed up cumulative rainfall curves and time distribution of daily rainfall in the specific area. Application of the used model in this research will  be ables us create the cumulative rainfall curves for each of the basin, which have the suitable rain gauge quantities.

In the present research a dibble punch planter with pneumatic seed metering device was constructed. These planters punch holes at equal distances and depths in soil and then place a single seed in each hole and cover it. The laboratory evaluation was conducted on grease belt. In this way, the effect of forward speed (2.8, 3.7, 4.6, 5.5, 6.4 and 7.3 km/h) on; multiple indexes, quality of feed index, miss index, precision and percent of holes with seed in them was considered. All of these indices based on theoretical distance between plants within a row and indicate the accuracy in seed placement for planters using single seed metering mechanisms. According to the results of these experiments the increase of forward speed resulted in increase of precision and decreasing the percent of holes with seed in them, without any remarkable effect on the multiple indexes, miss index and quality of feed index. Furthermore 6.4 km/h speed was recommended as the best forward speed.

The efficiency of in vitro shoot and microtuber formation of two comercial potato cultivars from single nodal cuttings were studied on solid and liquid MS basal medium applying different inoculation culture density.The experimental design , complete randomized with three replications was applied. Each replication per experimentation unit consisted of 10 erlenmeyers flask. The observations on number of shoot and microtuber per erlenmeyer flask were recorded 4 and 10 weeks after culture explants respectively.Results revealed that the number of microtubers and shoots were affected by the genotype, support of culture as well as inoculation density of culture. The highest reproduced number of microtuber belonged to Agria cultivar. Comparative studies between solid and liquid culture revealed that shoot and microtuber formation were more efficient in liquid medium. Mean comparison also showed that there are significant differences amoung three levels of inoculation density, so that 6 and 9 explants per erlenmeyer were superior compared to density of 3 explants per erlenmeyer concerning both trails under study.

In order to determinethe most important traits that affecting grain yield of corn, a field expriment was conducted similary in 1999 and 2000, in Khoramabad, as a split-factorial in randomise complated  block design in four replicates. Drought treatments were the plant irrigation after soil water reached 70% (without stress) , 60% (medium stress), and 50% (high stress) of  FC as a main factor and Zn(0, 10 and 20 kg/ha ZnSO4,7H2O) and P (0 and 150 kg/ha P2O5) as factorial were the factors of this design.Grain yield was positively correlated with yield components (ear No. per m2, row No. per ear, 100-grain weight), relative water content, leaf area index, biological yield and harvest index; but negatively correlated with straw yield. According to the stepwise regration analysis grain and straw yield were the most effects on harvest index, and on grain yield were yield components in different levels of drought stresses. Other traits affected on straw yield diffrently. Path analysis showed that grain yield was most direct effect on harvest index in different levels of drought stresses. Ear No. per m2 was the most effect on grain yield in without and medium stresses, but row No. per ear in high stress. With increasing in drought stress, the direct effect biological yield on straw yield was increased, showed that the effect of grain yield on harvest index decreased.

A study was carried out to evaluating some environmental effects on growth traits in a Zandi flock. Data of 5791 head of lambs during 1992 to 2002 on birth, weaning, 6-month, 12-month, average daily gain from birth to weaning and weaning to 6-month were analysed to calculat Least Squar Means (LSM) and test of significant effects on traits. According to the results, effects of sex, birth type, age of dam, and birth year were significant for all traits (p< 0.05). Interaction effects between sex by birth type were significant for all traits (p<0.05), between sex by age of dam were significant for all traits (p<0.05), except birh ewight and between birth type by age of dam were significant only for average daily gain traits (p<0.05). Overall Least Squar Means for these traits were 3.94±0.32; 19.41±0.30; 28.06±0.38; 30.30±0.57; 0.172±0.003 and 0.124±0.003 kg respectively.