Abstract: Yield and Crop Water Productivity are crucial issues
in sustainable agriculture, especially in high-demand resource crops such as sweet corn. This study was conducted to investigate
agronomic responses such as plant growth, yield and soil parameters (EC and Nitrate accumulation) to several deficit irrigation treatments
(100, 75, 50, 25 and 0% of ETm) applied during vegetative growth
stage, rainfed treatment was also tested.
The finding of this research indicates that under deficit irrigation
during vegetative growth stage applying 75% of ETm lead to increasing of 19.4% in terms of fresh ear yield, 9.4% in terms of dry grain yield, 10.5% in terms of number of ears per plant, 11.5% for
the 1000 grains weight and 19% in terms of crop water productivity compared with fully irrigated treatment. While those parameters in
addition to root, shoot and plant height has been affected by deficit
irrigation during vegetative growth stage when increasing water stress degree more than 50% of ETm.
Abstract: Post-anthesis drought stress is the most important
problem affecting wheat production in dryland fields, specially in
Mediterranean regions. The main objective of this research was to
evaluate drought tolerance indices in dryland wheat genotypes under
post-anthesis drought stress. The research was including two different
experiments. In each experiment, twenty dryland bread wheat
genotypes were sown in a randomized complete blocks design
(RCBD) with three replications. One of experiments belonged to
rain-fed conditions (post-anthesis drought stress) and other
experiment was under non-stress conditions (with supplemental
irrigation). Different drought tolerance indices include Stress
Tolerance (Tol), Mean Productivity (MP), Geometric Mean
Productivity (GMP), Stress Susceptibility Index (SSI), Stress
Tolerance Index (STI), Harmonic Mean (HAM), Yield Index (YI)
and Yield Stability Index (YSI) were evaluate based on grain yield
under rain-fed (Ys) and supplemental irrigation (Yp) environments.
G10 and G12 were the most tolerant genotypes based on TOL and
SSI. But, based on MP, GMP, STI, HAM and YI indices, G1 and G2
were selected. STI, GMP and MP indices had high correlation with
grain yield under rain-fed and supplementary irrigation conditions
and were recognized as appropriate indices to identify genotypes with
high grain yield and low sensitivity to drought stress environments.
Abstract: Silicon is a beneficial element for plant growth. It
helps plants to overcome multiple stresses, alleviates metal toxicity
and improves nutrient imbalance. Field experiment was conducted as
split-split plot arranged in a randomized complete block design with
four replications. Irrigation system include continues flooding and
deficit as main plots and nitrogen rates N0, N46, N92, and N138 kg/ha
as sub plots and silicon rates Si0 & Si500 kg/ha as sub-subplots.
Results indicate that grain yield had not significant difference
between irrigation systems. Flooding irrigation had higher biological
yield than deficit irrigation whereas, no significant difference in grain
and straw yield. Nitrogen application increased grain, biological and
straw yield. Silicon application increased grain, biological and straw
yield but, decreased harvest index. Flooding irrigation had higher
number of total tillers / hill than deficit irrigation, but deficit
irrigation had higher number of fertile tillers / hill than flooding
irrigation. Silicon increased number of filled spikelet and decreased
blank spikelet. With high nitrogen application decreased 1000-grain
weight. It can be concluded that if the nitrogen application was high
and water supplied was available we could have silicon application
until increase grain yield.
Abstract: In order to investigate water deficit stress on 24 of
soybean (Glycine Max. L) cultivars and lines in temperate climate, an
experiment was conducted in Iran Seed and Plant Improvement
Institute. Stress levels were irrigation after evaporation of 50, 100,
150 mm water from pan, class A. Randomized Completely Block
Design was arranged for each stress levels. Some traits such as, node
number, plant height, pod number per area, grain number per pod,
grain number per area, 1000 grains weight, grain yield and harvest
index were measured. Results showed that water deficit stress had
significant effect on node number, plant height, pod number per area,
grain number per pod, grain number per area, 1000 grains weight and
harvest index. Also all of agronomic traits except harvest index
influenced significantly by cultivars and lines. The least and most
grain yield was belonged to Ronak X Williams and M41 x Clark
respectively.
Abstract: The selection of parents and breeding strategies for
the successful maize hybrid production will be facilitated by
heterotic groupings of parental lines and determination of combining
abilities of them. Fourteen maize inbred lines, used in maize breeding
programs in Iran, were crossed in a diallel mating design. The 91 F1
hybrids and the 14 parental lines were studied during two years at
four locations of Iran for investigation of combining ability of
gentypes for grain yield and to determine heterotic patterns among
germplasm sources, using both, the Griffing-s method and the biplot
approach for diallel analysis. The graphical representation offered by
biplot analysis allowed a rapid and effective overview of general
combining ability (GCA) and specific combining ability (SCA)
effects of the inbred lines, their performance in crosses, as well as
grouping patterns of similar genotypes. GCA and SCA effects were
significant for grain yield (GY). Based on significant positive GCA
effects, the lines derived from LSC could be used as parent in crosses
to increase GY. The maximum best- parent heterosis values and
highest SCA effects resulted from crosses B73 × MO17 and A679 ×
MO17 for GY. The best heterotic patterns were LSC × RYD, which
would be potentially useful in maize breeding programs to obtain
high-yielding hybrids in the same climate of Iran.
Abstract: In order to evaluation the effects of soil organic
matter and biofertilizer on chickpea quality and biological
nitrogen fixation, field experiments were carried out in 2007
and 2008 growing seasons. In this research the effects of
different strategies for soil fertilization were investigated on
grain yield and yield component, minerals, organic compounds
and cooking time of chickpea. Experimental units were
arranged in split-split plots based on randomized complete
blocks with three replications. Main plots consisted of (G1):
establishing a mixed vegetation of Vicia panunica and
Hordeum vulgare and (G2): control, as green manure levels.
Also, five strategies for obtaining the base fertilizer
requirement including (N1): 20 t.ha-1 farmyard manure; (N2):
10 t.ha-1 compost; (N3): 75 kg.ha-1 triple super phosphate;
(N4): 10 t.ha-1 farmyard manure + 5 t.ha-1 compost and (N5):
10 t.ha-1 farmyard manure + 5 t.ha-1 compost + 50 kg.ha-1
triple super phosphate were considered in sub plots.
Furthermoree four levels of biofertilizers consisted of (B1):
Bacillus lentus + Pseudomonas putida; (B2): Trichoderma
harzianum; (B3): Bacillus lentus + Pseudomonas putida +
Trichoderma harzianum; and (B4): control (without
biofertilizers) were arranged in sub-sub plots. Results showed
that integrating biofertilizers (B3) and green manure (G1)
produced the highest grain yield. The highest amounts of yield
were obtained in G1×N5 interaction. Comparison of all 2-way
and 3-way interactions showed that G1N5B3 was determined
as the superior treatment. Significant increasing of N, P2O5,
K2O, Fe and Mg content in leaves and grains emphasized on
superiority of mentioned treatment because each one of these
nutrients has an approved role in chlorophyll synthesis and
photosynthesis abilities of the crops. The combined application
of compost, farmyard manure and chemical phosphorus (N5)
in addition to having the highest yield, had the best grain
quality due to high protein, starch and total sugar contents, low
crude fiber and reduced cooking time.