International Journal of Plant Production
Volume:2 Issue: 1, Jan 2008

Sorghum is a wonder crop from physiological point of view. It is the most important cereal crop, after rice and wheat. The number of reports describing the use of transgenic Sorghum for basic studies in Biotechnology is still limited when compared to other crops. In one hand, the success of the transformation techniques is mainly dependent upon the availability of optimal protocols for highly efficient tissue culture techniques. On the other hand, regeneration in Sorghum is difficult. Hence, in this study an efficient and reproducible method for in vitro development of embryogenic callus and regeneration in Sorghum bicolor was developed. Immature embryo explants of Sorghum bicolor were cultured on MS nutrient medium supplemented with different concentrations and combinations of auxins and cytokinins. Embryogenic callus was initiated on MS medium supplemented with 2 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5 mg/l Kinetin (KN). Addition of KN to MS medium containing 2,4-D resulted in a significant enhancement on embryogenesis of the embryos. Amino acids also supported an improved frequency of embryogenesis. Therefore induction of a high frequency of somatic embryogenesis in immature embryos on MS medium is possible. Development of embryogenic callus, induction of somatic embryo and subsequent shoot regeneration was proficient at a concentration of 2 mg/l BAP. The regenerated shoots readily rooted on half strength MS medium supplemented with 1 mg/l naphthalene acetic acid (NAA). The regenerated plantlets were successfully transferred to soil and subsequently plants produced seeds. There was no difference between the acclimatized plants in comparison with in vivo plants in the respect of morphological characters.

Genetic improvement of seed vigour and emergence of yellow-seeded flax (Linum usitatissimum L.) is important to have a good stand establishment, since they are negatively affected by yellow seed colour. This study was conducted to investigate genetic variation, broad-sense heritability and expected genetic response to selection for germination, seed vigour and field emergence. Sixteen genotypes of yellow-seeded flax and 17 of brown-seeded were evaluated for germination at 5°C, 15°C and vigour test (cold test) and also for field emergence in 2005 and 2006. Genetic variation for vigour test and field emergence in yellow-seeded genotypes was much higher than brown-seeded, as shown by their genetic coefficients of variation of 41% vs. 17.9% in vigour test, 50.9% vs. 3.8% and 34.1% vs. 18% for field emergence in 2005 and 2006, respectively. Germination of yellow and brown-seeded genotypes in vigour test varied from 10.7 to 55.3% and 40.7 to 88.7%, respectively. Field emergence ranged from 20 to 217.3 and 35 to 184.3 seedlings/m2 among yellow-seeded genotypes in 2005 and 2006; however, the corresponding range for brown-seeded genotypes was 266 to 414 and 93.7 to 210 seedlings/m2. Broad-sense heritability for germination at 5°C and vigour test, days to 50% emergence and seed weight were high (65.9 to 98.4%). The heritabilities for field emergence were low to moderate for brown seeds (6.7% and 51.6%), and moderate to high (56.2 % to 96.8%) for yellow seeds in 2005 and 2006. High estimates of genetic response to selection for seed vigour and field emergence were found in yellow-seeded genotypes, indicating the possibility of genetic improvement of these traits.

The objectives of this study were to assess the genotype (G) by environment (E) interaction of grain yield of durum wheat(Triticum durum Desf.) based on parametric models, additive main effects and multiplicative interaction (AMMI) and joint linear regression models; and compare the relative efficiency of the two models in explaining the GE effects. Twenty-three genotypes were evaluated across 12 environments (location-year combinations) in 2003 and 2004. Combined analysis of variance showed that the environment (E) accounted for a high percentage of sums of squares (remaining after removing the sums of squares due to error and replications). The genotypic variability of grain yield among genotypes was small. The best genotype 6 (DBSP02/8) out yielded the check by 0.24 ton/ha. Based on full AMMI model analysis, AMMI-1 was found to explain up to 94% of the main and interaction effects, and AMMI-2 was found to fully capture target percentage sums of squares in the GE interaction pattern. The biplot based on the first bilinear AMMI model terms indicated that genotype 7 (DBSP02/9) and genotype 19 (DBSP03/16) could be suited for cultivation across the test environments. However, no genotype had superior performance in all environments. Reitrivier normal planting date in 2003 (E403) was the most favorable environment for yield, whereas, Upington in 2003 (E603) was the least favorable one. Model comparison criteria showed that AMMI model was superior to joint regression model in terms of its predictive accuracy and efficiency of explaining the pattern of GE sum of squares. It was concluded that AMMI biplot clearly facilitate identification of mega-environments and cultivars for specific recommendations. The differential response of genotypes observed in this study reaffirms the necessity of multi location evaluations to identify superior and stable genotypes. However, trends in specific adaptation could be detected using the which-won-where pattern of the AMMI analysis, and site-specific breeding may be exploited when feasible.

Verticillium wilt is an economically important disease which inflicts serious losses in potato, cotton, alfalfa, some vegetable crops and fruit trees and occasionally ornamentals. Verticillium dahliae, infected cultivated species and weeds were collected from several areas in Iran during tewelve years from 1993-2005 and studied for their vegetative compatibility, host range and pathogenecity. The pathogen was isolated from 27 species belonging to 24 genera and 15 families of plants but was most frequently isolated from Solanaceae, Cucurbitaceae, Oleaceae and Rosaceae hosts. The morphology of V. dahliae isolates on Czapecks agar and water agar media were different especially for micosclerotial appearance time (4-19 days), pigmented zone of colony (37. 8-48. 33 mm) and microsclerotial morphology (abundant, irregular and elongated shaped or more spherical and scattered). The ratio index of length/width of conidia ranged between 2. 32 and 2. 70 micrometer with an average of 2. 43. 11. Temperature influenced the radial growth ratio of the isolates and the growth response of V. dahliae isolates to temperature in vitro was quadratic. All isolates were categorized in three groups based on pathogenecity tests on differential test plants (cotton cv. Sahel and eggplant cv. local). 548 V. dahliae isolates from different locations and hosts were assigned to vegetative compatibility groups (VCGs) using nitrate-nonutilizing (nit) mutants. A higher frequency of nit1/nit3 mutants (93%) were obtained compared to nitM (7%). 51. 1% of the isolates were assigned to VCG4B, 25. 9% to VCG2A and 23% to VCG1. The results demonstrated that V. dahliae isolates assigned to VCGs were closely associated with specific pathogenecity within the group/diverse.

An experiment was carried out to compare the effect of feeding posidonia australis as a non-conventional feedstuff with cereal straw for sheep maintenance; and to compare seagrass/chicken litter with lucerne hay and pasture for sheep production on a scale such as would be applicable to lot-feeding of sheep in the area of suthern Australia in case of short term feed scarcity. To approach this target a Randomized Completely Block Design with six treatments was applied on sixty adult merino. The six experimental diets were: (A) 75% treated seagrass% lucerne; (B) 75% treated wheat straw% lucerne; (C) 75% treated wheat straw% chicken litter (seagrass bedr‘œ manure from a 7-week broiler raising period); (D) 50% treated wheat straw% treated seagrass; (E) 100% treated straw; (F) Green pasture, mixture of legume and graminea. To treat seagrass and straw a solution containing 8% fertilizer grade urea, 15% sugarcane molasses and 1% calcium-diphosphate was mixed with either seagrass or straw (1 Kg/Kg DM). The mixture was stored under anaerobic conditions for 3 weeks. The total experimental period of 109 days was used to measure the effect of experimental rations on the voluntary intake, body weight gain, fat score, feed efficiency and wool growth rate of sheep. There were different DMI of diets A, B and C during the experiment but these differences were not significant. Similar results were obtained for diets D and E as well. Among sheep of groups A, B and C total body gain of the sheep in group A was significantly less than that of the other two groups. The body weight gain of sheep grazed on pasture was significantly less than that of the sheep groups B and C, more than for the sheep in groups D and E (P<0.05) and equal that of the to sheep group A. In general there were few statistical differences, except that sheep on diet A showed consistently lowest values for greasy and clean fleece weight, staple growth rate, length: diameter ratio and staple strength. There was not a significant difference in clean fleece growth rate between sheep grazed on pasture and sheep in diet groups B, C, D and E, but this value was higher than for sheep in group A. It can be suggested that seagrass litter can be used proportionally in a mixed diet to provide enough nutrients and energy for sheep production in time of drought or feed scarcity. Meanwhile the cheaper diets D (seagrass containing) or E (straw only) could be used with equal efficiency in a lot-feeding system.

In a 3-year experiment (2002-2004), five N rates (0, 60, 120, 180, 240 kg N ha-1) were applied to sugar beets arranged in a Randomized Complete Block design with six replications. Experimentation took place under the semi-arid, irrigated conditions of central Greece. The aim of this work was to study the late season response of sugar beet crop to N fertilization as assessed by non-destructive measurements of chlorophyll (SPAD) and Leaf Area Index (LAI). Physiological measurements were conducted from early August to mid-September, every two weeks. Sugar yield response to N fertilization was evident only in 2004. The highest root and sugar yields were found in 2002 as a result of the unusually high, for Mediterranean conditions, rainfall during summer. The highest petiole NO3-N concentrations and the lowest sucrose content in root fresh weight were also recorded in 2002. In 2003, sugar beets were water stressed at late August and thus LAI was minimum. Thus, the lowest root and sugar yields were found in 2003. In 2004, SPAD and LAI values were related with root and sugar yields. SPAD readings of ca 38.00 were the optimal for maximum yield. Optimal LAI values for root and sugar yields were 3.99 and 3.88, respectively. SPAD was, also, related with petiole NO3-N concentration and α-amino N in roots. A healthy and green canopy at the late stages of the growing season can contribute to high sugar beet yield. Optimal N rate for maximum root and sugar yield was close to or higher than 200 kg ha-1 N. Chlorophyll (SPAD) and LAI determination by instruments could be a sensitive tool in revealing sugar beet response to N fertilization and non-destructively assessing sugar beet N nutrition status.

Summer maize (Zea mays L.) is one of the dominant crops in the North China Plain (NCP). Its growth is greatly influenced by the spatial-temporal variation of climatic variables، especially solar radiation، temperature and rainfall. The WOFOST (version 7. 1) model was applied to evaluate the impact of climatic variability on summer maize yields using historical meteorological data from 1961 to 2000. The model was calibrated and validated using data from field experiments conducted during the period 1998-1999 and simulations were run to analyses the climate impact. Simulated potential yield ranges from 7. 7 to 10. 0 Mg ha-1، with an increasing trend from south to north، while rainfed yield ranges from 4. 3 to 8. 1 Mg ha-1، and with an increasing trend from the middle to the north and south of NCP. Gaps between potential and rainfed yields also decreased from the middle to the north and south. The pattern of potential yield was mainly attributed to the distribution of solar radiation and temperature، whereas rainfed yield was mainly influenced by the distribution of rainfall. Interannual variability n of potential yield is small، and was closely related to the variation of solar radiation، while rainfed yield varied greatly، especially in the middle of the plain، where the rainfall is lowest. Combined with consistent research results of winter wheat، results of this study offer scientific basis for policy makers and researchers concerned with the management of food marketing decisions and water resource reallocation

Little attention has been paid to the diagnosis of deficiencies of micronutrients such as zinc (Zn) and boron (B) and secondary nutrient such as sulphur (S) in rainfed systems. We evaluated Zn, B and S status of 1617 farmers’ fields in 14 districts of the semi-arid tropical India. Results showed that most of the soil samples were low to medium in organic carbon contents. Results also revealed that Zn deficiency ranged from 2 to 100%, B deficiency ranged form 0 to 100%, and S deficiency ranged from 40 to 100% in farmers’ fields across the districts. On-farm trials were conducted to study the response of rainfed crops to Zn, B and S application, and the residual effects of B and S, genotypic variations in chickpea cultivars in response to these nutrients and the economics of Zn, B and S use. Results from on-farm trials conducted during 2002-2006 showed significant yield responses of finger millet, maize, sunflower, soybean, groundnut and chickpea to application of Zn, B and S. There was significant residual effect of B and S applied to rainy season soybean on post-rainy season chickpea. Among genotypes of chickpea, KAK-2 was more responsive than other cultivars. Application of Zn, B and S also significantly increased the uptake of Zn, B and S in the crop biomass. Results also showed that application of Zn, B and S along with N was economical and critical for higher and sustained productivity of rainfed crops in semi-arid regions of India