International Journal of Plant Production
Volume:1 Issue: 2, Sep 2007

Ever since the arrival of the tomato to Spain in the 16th century, great diversification of the crop has taken place, giving rise to a rich collection of varietal types. The ‘Comunidad Valenciana’, with its deep-rooted agricultural tradition, is one of the Spanish regions with the greatest diversity in traditional tomato varieties, characterised by their local adaptation and high fruit quality. Nevertheless, traditional varieties of tomato have been progressively abandoned over recent decades. A survey was carried out in the ‘Huerta de Valencia’ area of the ‘Comunidad Valenciana’ in order to evaluate the factors involved in the genetic erosion of traditional tomato varieties, as a model of the process affecting vegetable crops in Europe. The growth of urban areas that absorb horticultural land, the change in agricultural techniques, the low profitability of farms and their small size, the advanced age of farmers, the conversion of vegetable gardens to other crops and the incidence of viral diseases, have been identified as the major factors affecting genetic erosion in this analysis. The development of resistant traditional varieties through a formal plant breeding programme, and the consolidation of the specialised markets that efficiently exploit the organoleptic quality of these varieties, would help to assure the profitability of these varieties, and hence their active conservation on an on-farm basis. Consequently, the loss of these materials that make up gene combinations of an outstanding value could be prevented, and farmers would obtain a profitable alternative in a highly competitive agriculture.

Improvement of seed yield and oil content in safflower (Carthamus tinctorius L.) as an oilseed crop is the main objective of its breeding programs. However, little genetic information is available for these traits. The main objective of this study was to estimate genetic parameters for seed yield and oil content. Six safflower lines each derived from different Iranian local populations and Saffire as a foreign cultivar were crossed in all combination as a diallel set without their reciprocals. Crosses were selfed to obtain seeds of F2 progenies. F1 and F2 progenies along with their parents were evaluated in two separate experiments to do F1 and F2 diallel analysis. The GCA mean squares were significant for all traits including seed yield per plant, heads per plant, seeds per head, 100-seed weight, days to flowering, plant height and oil content. In both analyses, positive GCA effects for seed yield were found for parental lines IUTE1449 and IUTH13, indicates that progeny with those genotypes as parents showed seed yields that were greater than the average of all crosses. The parental line IUTKH211 was the best combiner for developing genotypes with high oil content. For achieving genotypes with short time to flowering and plant height, Saffire was the best parent. GCA/SCA ratio indicated there were large additive effects for all the traits, except for seed yield per plant. Narrowsense heritability for seed yield per plant and oil content was 9.3 and 23.5%, receptively. However, seeds per head, 100-seed weight, days to flowering and plant height had moderate to high narrowsense heritability (79.8, 55.4, 65.6 and 89.4%, respectively). There was reasonable consistency for estimating genetic parameters from analysis of F1 and F2 progenies. .

Plant growth promoting rhizobacteria (PGPR) are known to influence plant growth by various direct or indirect mechanisms. In search of efficient PGPR strains with multiple activities, a total of 150 bacterial isolates belonging to Bacillus, Pseudomonas, Azotobacter and Rhizobium were isolated from different rhizospheric soil of chick pea in the vicinity of Allahabad. These test isolates were biochemically characterized and screened in vitro for their plant growth promoting traits like production of indoleacetic acid (IAA), ammonia (NH3), hydrogen cyanide (HCN), siderophore and catalase. All the isolates of Bacillus, Pseudomonas and Azotobacter produced IAA, whereas only 85.7% of Rhizobium was able to produce IAA. Production of ammonia was commonly detected in the isolates of Bacillus (95.0%) followed by Pseudomonas (94.2%), Rhizobium (74.2%) and Azotobacter (45.0%). All test isolates were positive for catalase but none of the isolates produced HCN. On the basis of multiple plant growth promoting activities, 20 bacterial isolates of each genus, in total 80 isolates, were evaluated for their heavy metal tolerance. Among these isolates, Bacillus spp. were tolerant to all the heavy metals (400 µg ml-1), whereas Pseudomonas spp. were tolerant to Hg (100 µg ml-1), Co (100 µg ml-1), Cd (200 µg ml-1), Cr (100 µg ml-1), Cu (200 µg ml-1), Pb (400 µg ml-1), Zn (200 µg ml-1). Tolerance to heavy metals was observed less frequently in Azotobacter spp. and Rhizobium spp. The isolates could exhibit more than two or three PGP traits, which may promote plant growth directly or indirectly or synergistically. Further, rhizobacteria tolerant to multiple heavy metals exhibited a couple of PGP activities.

A genetic map containing 103 microsatellite loci and 200 F2 plants derived from the cross R15 × Ye478 were used for mapping of quantitative trait loci (QTL) in maize (Zea mays L.). QTLs were characterized in a population of 200 F2:4 lines, derived from selfing the F2 plants, and were evaluated with two replications in two environments. QTL mapping analysis of plant height was performed by using QTLMapper 2.0 software. Three main-effect QTLs and seven pairs of distinctly epistatic loci included a total of fourteen QTLs were located on seven chromosomes. QTL main effects of additive, dominance, and additive × additive, additive × dominance, and dominance×dominance interactions were estimated. Interaction effects between QTL main effects and QTL×environments (QE) were also predicted. Less than 30% of single effects for identified QTLs were significant at 5% level. The information about epistatic QTLs and QE interaction will facilitate marker assisted selection for plant height breeding programs in maize.

Woody perennials subjected to root oxygen-stress often respond with varying levels of reduced assimilation and leaf gas exchange. Yet in most of these studies, seedlings grown in pots were subjected to experimental conditions that rarely exist in nature for mature trees. To determine if flooding mature orchard-grown pecan (Carya illinoiensis (Wangh) K. Koch) results in a similar depressed photosynthetic rate (Pn), transpiration (E), and stomatal conductance (gs) as found in potted seedling studies, 27 year-old trees were continuously flooded for 35 days during which gas exchange measurements were compared with non-flooded controls. Flood-treated trees exhibited a continuous decline in Pn, gs, and E without any apparent recovery throughout the treatment period, and progressively higher levels of intercellular CO2 (Ci). Flooded trees also exhibited widespread interveinal ‘bronzing’ in subtle blotchy patterns, sporadic adaxial interveinal scorching, and simultaneously put on a flush of new growth, not seen in the control trees. Mechanisms are considered relating a putative disruption in carbohydrate export to the reduced levels of photosynthesis

Xylem sap flux density (Fd) was measured, on a 43-year-old (mature) and three 4-year-old (young) mango (Mangifera indica L.) trees, using Granier-type probes. The relative influences of environmental variables were examined under well-watered condition. Circumferential variation in Fd was also investigated by placing sensors on the north, south-west and south-east sides of the mature tree. Sap flux density lagged solar radiation (Rs) by 30 min and led vapour pressure deficit (De) also by 30 min in the young trees whereas Fd lagged Rs by 60 min in the mature tree. However, the canopy of mature tree seems better coupled with the diurnal course of De as time lag between the paired series was zero. Maximum Fd occurred at 1330 h in the mature tree and 1130 h in the young trees. Significant (P<0.001) correlation was between most of the environmental factors and Fd for mango tree. No systematic differences in Fd were found between the north and other aspects (sides) of the mature tree. Instead they had close relation with each other (r2> 0.98). However, Fd from the south-west side of the 43-year-old tree was 4.2% and 18.3% higher on a typically bright and partially clouded days while Fd from south-east side was lower with about 4.4% and 1.1%, respectively, compared with Fd on the north. This indicates the possibility of transpiration enhancement in response to wind advection from the nearby village in the south-west direction. Identification of the relative influence of these environmental factors on sap flow may provide basis for an in-depth analysis of the control of transpiration in rain-fed mango trees both under plantation and agroforestry systems in West Africa.

It has been reported that in different regions and sowing dates, the response of crops to past climate change is not the same, due to different rates of decrease/increase in each climatic variable at different regions and months of year. This study was aimed to assess the effect of individual versus simultaneous changes in solar radiation (S), precipitation (P) and temperature (T) on rainfed- and irrigated-chickpea, using model CYRUS. The observed weather data for year 2004 in Kermanshah, Iran, was used as the control. Firstly, the responses of chickpea to individual changes in S and P (25, 50, 75, 125 and 150%) and T (±1, ±2oC) with respect to control were studied. Secondly, S, P, and T were simultaneously changed by 50%, 150%, and ±2°C, and the interactions were analyzed. Results indicated that the value of change in biomass, harvest index (HI) and evapotranspiration (ET) was higher for S, compared to P and T. For irrigated-chickpea, the biomass and ET were directly, but HI (nearly) inversely affected by S. T had no impact on HI and ET. The biomass was slightly lower for warmer T. When T, S and P were simultaneously changed, P and T slightly interacted with huge effect of S. For rainfed-chickpea, it was found non-linear response to S for biomass, but linear response for HI. For high S levels, ET was same as control. The decreased levels of P positively affected biomass and HI. There was proportionally change in biomass and HI with changing T. It was found various considerable interactions between variables for biomass, HI and ET. For example, when T was cool, high values of S and P synergistically decreased biomass. These single- and interaction-based results would be adapted as one possible scenario of multi-parameter sensitivity analysis, and could be useful for identifying appropriate management/genotypes for future climate.

Contamination of plants and waters with nitrate and sodium is an important environmental problem that can affects humans. An experiment was carried out aiming to evaluate the effect of fertilization and irrigation water quality on NO3- and Na contents of drained water and lettuce (Lactuca sativa L.) plants in Rio Claro, São Paulo State, Brazil. Treatments were distributed in a factorial arrangement 5 x 2, referring to fertilization and irrigation water quality (treated and polluted water), respectively, with three repetitions. The following fertilizers were used: Biofertilizer (BIO), bovine manure (BM), poultry manure (PM) and mineral fertilizer (MF). Additionally a non fertilized (NF) treatment also was studied. The following variables were registered: a) Drained water: Nitrate and sodium contents and presence of fecal and total coliforms; b) Lettuce leaves: nitrate content. The average nitrate and sodium contents of drained water indicated that contamination slowly advances on soil profile in areas of disposal of organic and inorganic residues. The fertilizer used on lettuce cultivation affected sodium and nitrate contents of leaves and drained water, and, in contrast irrigation water quality had no effect.

Environmental (topography, climate) features have an important influence on plant diversity and richness of Iran. On the basis of environmental factors, four ecological zones with specific plant richness from lowest area to highest area (Hyrcanian, Khalij-o-Omani, Zagross and Iran-o-Touranian zones) were established respectively. Topography is from –28m which is close to Caspian Sea to 5678m which is located on the Alborz Mountain. Two mountains (Alborz and Zagross) prevent moist air moving to the centre of Iran. Northern Iran is rich in biodiversity with 8000 plant species representative of many different life forms (Herb, Grass, Shrub and tree) in the Hyrcanian zone that is located north of. 35oN latitude. In contrast, the lowest plant diversity is in the southern part of Iran (Khalij-o-Omanian zone), which is a flat area. The vast central plateau (Iran-o-Touranian) is divided into two divisions with mountain part and an area of high plains. The western part of Iran (Zagross zone) is affected by Mediterranean and Black sea moisture which brings snow in the winter. The dominant species are low growing plant species with forbs, grass, shrub and tree life forms. Topography and climate factors interact to plant influence distribution and richness of Iran and they play an important role in creating microniches that foster great ecological biodiversity of this country.

Evaluating agricultural land management practices requires knowledge of soil spatial variability and understanding their relationships. Spatial distributions for fourteen soil physical and chemical properties were examined in a wheat field in Sorkhankalateh district, in Golestan province, Iran. 101 soil samples at the distances of 5m, 10m and 20m as nested grid were collected at the depth of 0-30cm in early December 2004 just after planting the winter wheat in a plot (1.8 ha area). Data were analyzed both statistically and geostatistically on the basis of the semivariogram. Frequency distribution of all data was normal. The spatial distribution and spatial dependence level varied within location. The range of spatial dependence was found to vary within soil parameters. Nitrate had the shortest range of spatial dependence (23.99m) and K had the longest (93.92m). Eight parameters including pH, EC, sand, silt, clay, P, CaCO3 and organic matter (OM) were moderately spatially dependent whereas saturation percentage (SP), bulk density (Db), K, N, cation exchange capacity (CEC) and exchangeable sodium percentage (ESP) were strongly spatially dependent. The results demonstrate that within the same field, spatial patterns may vary among several soil parameters. Soil nutrients were found to be affected by farmer management. Variography and kriging can be useful tools for designing effective soil sampling strategies and variable rate application of inputs for use in site-specific management.