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Differences in water balance components of two maize hybrids were investigated at the Agrometeorological Research Station of Keszthely, during the 1997–98 growing seasons. The length of the vegetative period of the two maize varieties was the same, only their water necessities differed significantly. Daily sums of evapotranspiration were measured in lysimeter growing chambers. Alteration in water loss of the two maize varieties was also characterised by daily mean stomatal resistances. Modification in the process of water exchange between the plant and its environment was determined by calculating the complex parameter of Crop Water Stress Index (CWSI). Surprisingly, at non limited watering level the water consumption of the two hybrids was almost the same. The stomatal resistance of the drought tolerant hybrid increased together with its plant temperature and CWSI, comparing to the parameters of other maize variety, that was bred for irrigated conditions. Decreased transpiration might increase the plant temperature and CWSI of drought tolerant hybrid. This relation can be successfully applied in the process of selecting plants for different watering levels.
The present study was carried out during the three successive growing seasons of 1996, 1997 and 1998 to estimate the additive, dominance and epistatic components of genetic variation for the yield, yield components and wilt infection by using ninety triple test cross families and their parents, F1 and F2 in four sesame crosses. A randomized complete block design with three replications was used. The results indicated that mean squares of the genetic analysis of variance and the overall epistatic gene effects for the crosses showed highly significant differences for all studied characters. The [i] type (additive × additive) was considered as a major component of the overall epistatic effects for 1000-seed weight in the TTC3 cross, wilt infection percentage in TTC3 and TTC4, number of capsules/plant in TTC1, TTC2 and TTC4 and seed yield/plant in all crosses. The ratio of (H/D)1 for all crosses confirms the presence of partial dominance for all studied traits. The direction of dominance was positive and significant for wilt infection in TTC4, oil percentage in TTC1 and TTC4, number of capsules/plant and 1000-seed weight in TTC2 and seed yield/plant in all four crosses. The results also revealed that the highest proportion of recombinant lines was obtained for number of capsules/plant, 1000-seed weight and oil percentage in the TTC2 cross and for seed yield/plant in TTC3.
A study on the Auchenorrhyncha insects was performed in 2009 in Romanian commercial vine plots with different varieties and pest control intensities from Murfatlar, Banu Mărăcine and Blaj viticultural regions and in an untreated neglected plot near Bucharest exhibiting symptoms of yellowing or reddening. The aim of this study was to obtain information related to the presence of the potential vector insects associated with the grapevine yellows type-diseases symptoms from Flavescene dorée and Bois noir groups. Insects were sampled using yellow sticky traps. In the course of identifying potential phytoplasma vectors in vineyards, 21 species of leafhoppers and planthoppers were identified. Included in these are two very important vectors of phytoplasma throughout Europe: Hyalesthes obsoletus and Scaphoideus titanus.While H. obsoletus were only captured in low numbers, S. titanus was captured in higher numbers and showed two distinct population peaks throughout the growing season. Identification of phytoplasma vectors is critical to the national strategy for assessment and control of vectors spreading phytoplasma disease in Romanian vineyards.
. (Growing season stability of wheat varieties under different ecological conditions and the methods of the evaluations). Növénytermelés , 28, 89-105. Búzafajták tenyészidejének stabilitása különbözo ökológiai viszonyok között és az
Green manuring is considered an important agronomic practice for smallholder farming systems in the tropics. Different species of legumes and non-legumes are applied either as ex situ or in situ green manures. Thus a field study conducted under rainfed conditions in Sri Lanka compared the effect of in situ and ex situ green manuring using two popular green manures ( Crotolaria juncea — a legume and Tithonia diversifolia — a non-legume) on the growth, seed yield and N use pattern of maize ( Zea mays ), the most popular upland cereal in the Asian tropics, grown with high and low N rates, in the two seasons that correspond to the monsoonal rains. In situ green manuring, especially with crotolaria, increased the growth, seed yield and N use efficiency of maize when compared to the ex situ addition of similar quantities of the green manure. The impact was also greater in the minor season, when the crop was subjected to moisture stress conditions. The benefits of in situ green manuring with tithonia were lower than those due to crotolaria. In situ green manuring with tithonia also led to a greater increase in growth, seed yield and N use efficiency in maize compared to ex situ green manuring with this species. The green manures, especially in situ application, also increased the benefits of enhanced rates of N fertilizer to the crops in both seasons, with greater use efficiency in the major season. The study showed the benefits of green manuring (both in and ex situ ) for obtaining higher yields of maize in the growing seasons of the Asian tropics, especially the in situ application of legume species.
A field experiment was conducted at the Agriculture Faculty Farm of Sebha University during the 2007/2008 and 2008/2009 winter seasons to study the agronomic performance of seven pea genotypes with different sowing dates in sandy soil. The experiment was laid out in a randomized complete block design (RCBD) using a split-plot arrangement with three replicates. The five sowing dates (30 October, 15 November, 30 November, 15 December and 30 December) were assigned to the main plots, while the seven pea genotypes (Ambassador, Pollon, MG130256, G22765-2c, 89-P-109-11, No. 252, Victory Freezer and Master B) were allocated to the sub-plots. The sowing dates had a significant effect on all the studied traits except seed protein content in both seasons. Early sowing (15 November) was better than the other sowing dates for all the traits except 100-seed weight. There were significant differences between the pea genotypes for all the traits in the two growing seasons. The Victory Freezer genotype surpassed the other genotypes for all traits except number of branches plant-1 in the second season, 100-seed weight and seed protein content. The highest values for number of branches plant−1 in the second season and for seed protein content were obtained for the G22765-2c genotype, while the maximum values of 100-seed weight were recorded for the MG130256 genotype. A significant interaction between sowing dates and pea genotypes was detected for the length of the period from emergence to initial flowering, number of pods plant−1, seed yield plant−1 and seed yield ha-1 in both seasons. The longest period from emergence to initial flowering was obtained for the Victory Freezer pea variety sown on 30 November, while the highest values of pods plant−1, seed yield plant−1 and seed yield ha−1 were gained by sowing the Victory Freezer pea genotype on 15 November.
A 2-year conservation agriculture experiment was conducted in Southern Italy on durum wheat continuous cropping. Aim of the research was to assess the durum wheat productivity and grain quality in reduced soil tillage systems, according to conservation agriculture principles. The interactions among experimental treatments and climate revealed a close relationship among grain yield, grain quality and wheat growth conditions. Specifically, conventional tillage (CT, plowing and 2 disc harrowing) showed in the 2-year period higher grain production than reduced tillage treatments, minimum (MT, 1 disc harrowing) and No tillage (NT), especially for good crop water availability (3.29 t ha–1 of grain yield in CT, 2.67 in MT and 2.54 in NT). The amount of rainfall (above the average in both years) and its distribution in the growing seasons (more regular in the first year) strongly influenced wheat-grain quality indices (11.97% of protein content in the first year and 9.82% in the second one). Also, the wheat quality resulted more sensitive to the “Year × Tillage” interaction, with differences among tillages more evident in the second year and favourable to NT and MT. Spectral vegetation indexes (NDVI and TVI) measurements at flowering, have been shown to be useful to support farmers in N-late application for improving grain wheat quality. From this experiment carried out during the conversion period and in wet years, wheat managed with CT resulted in higher grain yield and quality, while only test weight showed a significant “Year × Tillage” interaction. Further indications emerged on the need to supply additional (10–20%) seed amount at sowing and crop nitrogen fertilizer in the first transition years in reduced tillage systems compared to conventional ones.
High-yield common buckwheat ‘cv. Fengtian 1’ (FT1) and tartary buckwheat ‘cv. Jingqiao 2’ (JQ2) were selected to investigate the characteristics of the grain-filling process and starch accumulation of high-yield buckwheat. FT1 had an average yield that was 43.0% higher than that of the control ‘cv. Tongliaobendixiaoli’ (TLBDXL) in two growing seasons, while JQ2 had an average yield that was 27.3% higher than that of the control ‘cv. Chuanqiao 2’ (CQ2). The Richards equation was utilized to evaluate the grain-filling process of buckwheat. Both FT1 and JQ2 showed higher values of initial growth power and final grain weight and longer linear increase phase, compared with respective control. These values suggest that the higher initial increasing rate and the longer active growth period during grain filling play important roles to increase buckwheat yield. Similar patterns of starch, amylose and amylopectin accumulation were detected in common buckwheat, leading to similar concentration of each constituent at maturity in FT1 and TLBDXL. Tartary buckwheat showed an increasing accumulation pattern of amylose in developing seeds, which differed from that of starch and amylopectin. This pattern led to a significant difference of the concentrations of amylose and amylopectin at maturity between JQ2 and CQ2, the mechanisms of which remained unclear. Nevertheless, both FT1 and JQ2 showed increased starch, amylose, and amylopectin accumulation during the physiological maturity of grains. The results suggest that prolonging the active grain-filling period to increase carbohydrate partitioning from source to seed sink can be an effective strategy to improve buckwheat yield.
Grain protein content (GPC) in durum wheat is a crucial determinant of pasta quality and as such is an important economic factor. This study was carried out to determine the microsatellite markers (SSRs) as associated with GPC in durum wheat grown under normal and moisture stress conditions. F3 and F4 population derived from 151 F2 individuals developed from a cross between Oste-Gata (drought tolerant) and Massara-1 (drought susceptible) genotypes, were used. The population was evaluated under four environmental conditions (two irrigation regimes in two growing seasons). The results of single marker regression analysis (SMA) revealed that 2, 4 and 10 markers to be associated with GPC, test weight (TW) and 1000 grain weight (TGW), respectively. These markers explained between 4.4 and 21.8% of the phenotypic variation in either environmental condition. The most significant marker observed for GPC was located on 5B chromosome near Xgwm408 under normal conditions and the other marker was observed on 1A, explaining about 15% of phenotypic variance. However, it was not recognized any marker related to GPC under drought stress conditions. Xgwm408 marker was coincident with the markers identified for TW, TGW and components of grain yield under drought stress conditions. In spite of 5B, the other chromosomes such as 2B and 3B were related to quantitative traits like TW and TGW. Composite interval mapping (CIM) identified 4 and 5 putative minor and major QTL for TW and TGW, respectively. Two QTL near Xbarc101 and Xbarc124 markers on 3B and 2B chromosome, explained up to 45.2 and 6% of phenotypic variations of TGW and TW, respectively.
Ten winter wheat ( Triticum aestivum L.) cultivars were tested in randomized complete block design (RCBD) trials at one location (Osijek) for several agronomic and quality traits through six growing seasons (1996/97–2001/02). Data were employed to develop modeling strategy for exploring genotype by environment interaction (GEI) by using models based on information on genotypic and environmental variables. The relative size, hence importance of the GEI compared to main effects of genotypes and environments was estimated for all effects from simple additive model (genotypes, environments and residuals, last including both GEI and experimental error) while the AMMI2 model was used as a basis for comparison of the GEI patterns. The final step in modeling strategy was fitting factorial regression models to all analyzed traits using available genotypic and environmental covariates, until the best fit solution was found for each analyzed trait.Comparing the relative sizes of genotypic and GEI effects, the last one was sizeable smaller, for all traits except grain yield (GY), thousand-kernel weight (TKW), and Hagberg falling number (HFN). Fitting of genotypic and environmental covariates resulted in various solutions for different traits, most frequently employing single genotypic covariate — Glu-A1.Regardless of their relatively small size, the GEI effects in wheat quality traits can offer a better insight into fluctuations of varietal quality over a range of environmental conditions, as they can be successfully modeled using various genotypic and environmental covariates. The advantage of described approach is attainable in virtually any breeding program, because during the implementation of the program breeders routinely score for a number of genotypic and environmental variables.
