scholarly journals Effect of terminal drought on yield and some physiological traits of winter wheat

Genetika ◽  
2018 ◽  
Vol 50 (2) ◽  
pp. 747-753 ◽  
Author(s):  
Ivanka Habus-Jercic ◽  
Marijana Baric ◽  
Snjezana Keresa ◽  
Anita Bosnjak-Mihovilovic ◽  
Milan Poljak ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Yield Components ◽  
Grain Filling ◽  
Grain Weight ◽  
Physiological Traits ◽  
Stay Green ◽  
Terminal Drought ◽  
Filling Phase ◽  
Green Strategy

Terminal drought i.e. drought during grain-filling phase is the most devastating environmental stress to wheat production. In present study the effect of terminal drought on physiological traits and its influence on yield and yield components in two winter wheat varieties (Kuna and Karla) were investigated. Terminal drought stress was applied from the beginning of anthesis by installing mobile plastic roof above the crops. Leaf gas exchange parameters, chlorophyll content index (CCI), relative water content (RWC), and nitrogen (N) content were measured three times during grain-filling phase, at early milk maturity (EMM), late milk maturity (LMM), and at early wax maturity (EWM). Grain yield and 1000 grain weight were measured by harvesting of each plot at crop maturity. Terminal drought enhanced leaf senescence and caused reduction of RWC, CCI, net photosynthetic rate (A), stomatal conductance (gs), and transpiration rate (E) as well as, grain yield and all measured yield components. However, grain yield and grain weight per ear were less affected in Karla indicating enhanced tolerance to terminal drought compared to Kuna variety. Higher tolerance to terminal drought in Karla is based on stay-green strategy. Stay-green strategy in Karla was characterized by retention of CCI at early wax maturity, which contributed to higher E and lower intercellular CO2 concentration compared to Kuna under terminal drought. Stay-green strategy as trait that enhanced terminal drought tolerance in Karla should be used in breeding programs and utilized to ensure maximum economic yields under terminal drought conditions.

QTL dissection of yield components and morpho-physiological traits in a durum wheat elite population tested in contrasting thermo-pluviometric conditions

2014 ◽  
Vol 65 (1) ◽  
pp. 80 ◽  
Author(s):  
M. Graziani ◽  
M. Maccaferri ◽  
C. Royo ◽  
F. Salvatorelli ◽  
R. Tuberosa
Keyword(s):  
Grain Yield ◽  
Durum Wheat ◽  
Adaptive Response ◽  
Yield Components ◽  
Positional Cloning ◽  
Recombinant Inbred Lines ◽  
Grain Filling ◽  
Kernel Weight ◽  
Physiological Traits ◽  
Peduncle Length

Dissection of the genetic basis of the adaptive response of durum wheat to unfavourable water and temperature regimes is an important prerequisite for the selection of genotypes less vulnerable to environmental constraints. An elite durum population of 249 recombinant inbred lines was tested across 16 Mediterranean environments characterised by contrasting thermo-pluviometric conditions and, consequently, a broad range of productivity (from 0.56 to 5.88 t  ha–1). Among the environmental variables investigated, soil moisture during grain filling showed the most consistent correlation with yield components and grain yield, whereas a weaker, albeit in some cases significant, association was noted with temperature at heading and thermal time during grain filling. Ear peduncle length appeared as a valid and easy-to-phenotype morphological proxy for the water available to the plant. In total, 76 quantitative trait loci (QTLs) were identified for yield components and for several morpho-physiological traits (peduncle length, the spectral reflectance index NDVI and leaf greenness at the milk-grain stage expressed in SPAD units) associated with the adaptive response of wheat to water and heat stresses. Although most of the QTLs were significant in only one or two environments, two major QTLs on chromosomes 2BL and 3BS showed consistent additive and epistatic effects on 1000-kernel weight, peduncle length, SPAD values and grain yield in half of the environments. In view of their strong phenotypic effects on kernel weight, these two QTLs are good candidates for positional cloning in order to gain a better understanding of the functional basis of their effect on the plasticity of grain weight and grain yield.

Identification of yield limiting phenological phases of oats to improve crop management

2016 ◽  
Vol 155 (1) ◽  
pp. 1-17 ◽  
Author(s):  
J. M. FINNAN ◽  
J. SPINK
Keyword(s):  
Grain Yield ◽  
Management Practices ◽  
Management Strategies ◽  
Crop Management ◽  
Grain Filling ◽  
Grain Weight ◽  
Grain Number ◽  
Filling Phase ◽  
Naked Oats ◽  
Phenological Phases

SUMMARYThe optimization of management practices for oats is hindered by a lack of knowledge of the critical phenological phases at which management should be focussed. The objective of the present review was to identify the yield-limiting phases in the growth of the oat crop in order to optimize management and to maximize yield. The methodology employed was to identify characteristics associated with either the pre-anthesis grain number determination phase or with the post-anthesis grain filling phase. Characteristics associated with the pre-anthesis phase were identified as a positive linear relationship between yield and grain number, in addition to insensitivity of grain weight to changes in assimilate supply. Characteristics associated with the post-anthesis grain filling phase were identified as an absence of a relationship between yield and sink size (grain number) and changes in grain weight in response to changes in assimilate supply. Data was taken from published literature. Yields of both winter- and spring-sown hulled oats increased linearly with grain number showing a strong influence of grain number on yield. Grain weight of both winter- and spring-hulled oats, however, decreased with increasing grain number suggesting that competition for assimilates may exist at high grain number. Further evidence of the influence of assimilate supply on grain yield was obtained from several studies which showed that yield increased with leaf area duration as well as from studies where grain weight was found to decrease after reductions in assimilate supply per grain, whereas grain weight increased when assimilate supply to grain was increased. Oat crops also feature a grain abortion mechanism when assimilate supply is constrained. Yield of naked oats increased with grain number before reaching a plateau, a trend which suggests source limitation at high grain numbers. The available evidence suggests that yield is primarily determined by grain number determination but that grain yield is also potentially limited by assimilate availability in the post-anthesis period. It is recommended that crop management strategies for oats should aim both to increase grain number in the pre-anthesis period but also prolong the grain filling period after anthesis. Such a post-anthesis strategy should both reduce the possibility of yield being limited by assimilate availability and compensate for the production of smaller grains at higher grain numbers.

OPTIMIZED TIMING OF USING CANOPY TEMPERATURE TO SELECT HIGH-YIELDING CULTIVARS OF WINTER WHEAT UNDER DIFFERENT WATER REGIMES

2016 ◽  
Vol 54 (2) ◽  
pp. 257-272 ◽  
Author(s):  
XIAOYU ZHANG ◽  
XIYING ZHANG ◽  
SUYING CHEN ◽  
HONGYONG SUN ◽  
LIWEI SHAO ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Crop Production ◽  
Field Experiments ◽  
Potential Evapotranspiration ◽  
Canopy Temperature ◽  
Grain Filling ◽  
Physiological Traits ◽  
Growth Stages ◽  
Water Regimes

SUMMARYSelecting high-yielding cultivars under drought is an important practice to improve crop production. Canopy temperature (T) shows a relative reliable association with grain yield. In this study, we compared the suitability of canopy T and other agronomic as well as physiological traits associated with grain yield under different water regimes. Field experiments over two seasons (2011–2012 and 2012–2013) were carried out under three water regimes, represented about 64, 76 and 89% of potential evapotranspiration, with 16 local winter wheat (Triticum aestivum L.) cultivars in each season. Results showed that cultivars with higher yield usually performed consistently lower canopy T under three water regimes, while the relationships of grain yield with other agronomic or physiological traits were more influenced by soil moisture. In addition, the relationship between canopy T and grain yield varied with different growth stages: From the time of heading to early grain filling stages, a more significant negative linear relationship (p < 0.001) existed under the three irrigation levels.

scholarly journals Rattail fescue (Vulpia myuros) interference and seed production as affected by sowing time and crop density in winter wheat

Weed Science ◽  
2020 ◽  
pp. 1-10
Author(s):  
Muhammad Javaid Akhter ◽  
Per Kudsk ◽  
Solvejg Kopp Mathiassen ◽  
Bo Melander
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Seed Production ◽  
Yield Components ◽  
Field Experiments ◽  
Growing Season ◽  
Sowing Time ◽  
Growing Seasons ◽  
Crop Density ◽  
Wide Range

Abstract Field experiments were conducted in the growing seasons of 2017 to 2018 and 2018 to 2019 to evaluate the competitive effects of rattail fescue [Vulpia myuros (L.) C.C. Gmel.] in winter wheat (Triticum aestivum L.) and to assess whether delayed crop sowing and increased crop density influence the emergence, competitiveness, and fecundity of V. myuros. Cumulative emergence showed the potential of V. myuros to emerge rapidly and under a wide range of climatic conditions with no effect of crop density and variable effects of sowing time between the two experiments. Grain yield and yield components were negatively affected by increasing V. myuros density. The relationship between grain yield and V. myuros density was not influenced by sowing time or by crop density, but crop–weed competition was strongly influenced by growing conditions. Due to very different weather conditions, grain yield reductions were lower in the growing season of 2017 to 2018 than in 2018 to 2019, with maximum grain yield losses of 22% and 50% in the two growing seasons, respectively. The yield components, number of crop ears per square meter, and 1,000-kernel weight were affected almost equally, reflecting that V. myuros’s competition with winter wheat occurred both early and late in the growing season. Seed production of V. myuros was suppressed by delaying sowing and increasing crop density. The impacts of delayed sowing and increasing crop density on seed production of V. myuros highlight the potential of these cultural weed control tactics in the long-term management programs of this species.

Mid-parent advantage and heterosis in F1 hybrids of wheat from crosses among old and modern varieties

1998 ◽  
Vol 130 (3) ◽  
pp. 287-295 ◽  
Author(s):  
C. L. MORGAN
Keyword(s):  
Grain Yield ◽  
Yield Components ◽  
Field Trials ◽  
Yield Component ◽  
Grain Weight ◽  
F1 Hybrids ◽  
Phenotypic Differences ◽  
Beneficial Effects ◽  
Positive Heterosis ◽  
Modern Varieties

Twenty-eight F1 hybrids of wheat and their parents were grown in field trials at Trumpington, Cambridge during 1986/87 and 1987/88. They were derived from crosses between seven ‘modern’ varieties, used as female parents, and either two ‘old’ (Squareheads Master and Partridge) or two ‘modern’ varieties (Bert and Motto), which were used as male parents. Grain yield, yield components, biomass and height were determined. The male parents were chosen to provide contrasting phenotypes and genetic backgrounds for the F1 hybrids. Mid-parent advantage, the increase of a hybrid for a given character above the mean of its parents, and heterosis, the increase of a hybrid above the ‘better’ parent for that character, were calculated. Most F1 hybrids showed mid-parent advantage for the characters studied. This tended to be greatest for hybrids derived from parents with the largest phenotypic differences in that character. In contrast, where heterosis occurred it tended to be greatest where the phenotypic difference between the parents was least. This suggests that the beneficial effects of hybridization, resulting from the dispersion of dominant genes between the parents, was insufficient to overcome the detrimental effects of other genes present where the ‘less good’ parent was substantially lower than the ‘better’ parent. Hybrids derived from the ‘modern’ male parents had greater heterosis for grain yield and mean grain weight than those from the ‘old’ parents. Of the yield components, positive heterosis for mean grain weight resulted in heavier seeds and was the most important yield component in determining heterosis in grain yield. Heterosis for the number of grains/ear was small or did not differ significantly from zero while number of ears/m2 showed negative heterosis resulting in fewer ears/m2 in the hybrids.

Path Analysis of Red Rice (Oryza sativaL.) Competition by Cultivated Rice

Weed Science ◽  
1992 ◽  
Vol 40 (2) ◽  
pp. 313-319 ◽  
Author(s):  
D. J. Pantone ◽  
J. B. Baker ◽  
P. W. Jordan
Keyword(s):  
Grain Yield ◽  
Path Analysis ◽  
Yield Components ◽  
Field Experiments ◽  
Weight Percent ◽  
Grain Weight ◽  
Research Station ◽  
Direct Effects ◽  
Red Rice ◽  
Cultivated Rice

During 1985 to 1989, a series of field experiments were conducted at the Rice Research Station in Crowley, LA. Path analysis was employed to evaluate the competitive interaction between a weed (red rice) and cultivated rice (Mars). The path analysis quantified direct effects of red rice and Mars rice densities on the yield components (grain weight, percent filled florets, number of florets panicle−1, and panicles plant−1) of red rice and Mars rice. The model illustrated the direct and indirect effects of the yield components on fecundity and grain yield plant−1. The direct effects of Mars and red rice densities on panicles plant−1and florets panicle−1were always negative. In contrast, the effects of density on percent filled florets and grain weight varied from positive to negative and were relatively small, implying that they were determined primarily by density-independent factors. Path analysis indicated that the number of panicles plant−1and florets panicle−1were the most important yield components determining the responses of fecundity and grain yield to competition.

scholarly journals Carbohydrate Dynamics in Maize Leaves and Developing Ears in Response to Nitrogen Application

Agronomy ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 302 ◽  
Author(s):  
Peng Ning ◽  
Yunfeng Peng ◽  
Felix Fritschi
Keyword(s):  
Grain Yield ◽  
Grain Filling ◽  
N Fertilization ◽  
Starch Accumulation ◽  
N Availability ◽  
Maize Grain Yield ◽  
Filling Phase ◽  
Maize Grain ◽  
Carbohydrate Dynamics ◽  
Maize Ear

Maize grain yield is considered to be highly associated with ear and leaf carbohydrate dynamics during the critical period bracketing silking and during the fast grain filling phase. However, a full understanding of how differences in N availability/plant N status influence carbohydrate dynamics and processes underlying yield formation remains elusive. Two field experiments were conducted to examine maize ear development, grain yield and the dynamics of carbohydrates in maize ear leaves and developing ears in response to differences in N availability. Increasing N availability stimulated ear growth during the critical two weeks bracketing silking and during the fast grain-filling phase, consequently resulting in greater maize grain yield. In ear leaves, sucrose and starch concentrations exhibited an obvious diurnal pattern at both silking and 20 days after silking, and N fertilization led to more carbon flux to sucrose biosynthesis than to starch accumulation. The elevated transcript abundance of key genes involved in starch biosynthesis and maltose export, as well as the sugar transporters (SWEETs) important for phloem loading, indicated greater starch turnover and sucrose export from leaves under N-fertilized conditions. In developing ears, N fertilization likely enhanced the cleavage of sucrose to glucose and fructose in the cob prior to and at silking and the synthesis from glucose and fructose to sucrose in the kernels after silking, and thus increasing kernel setting and filling. At the end, we propose a source-sink carbon partitioning framework to illustrates how N application influences carbon assimilation in leaves, transport, and conversions in developing reproductive tissues, ultimately leading to greater yield.

scholarly journals Variability of grain yield components of some new winter wheat genotypes (Triticum aestivum L.)

2011 ◽  
Vol 48 (No. 5) ◽  
pp. 230-235
Author(s):  
M. Sabo ◽  
M. Bede ◽  
Ž.U. Hardi
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Yield Components ◽  
Vegetation Period ◽  
Grain Number ◽  
Potential Yield ◽  
High Positive Correlation ◽  
Wheat Genotypes ◽  
Grain Number Per Spike ◽  
Grain Yield Components

Variability of grain yield components of some new winter wheat genotypes (e.g. Lara, Lenta, Kruna, Fiesta, Perla, and one line of AG-45) was examined. The analysis of grain yield components of these genotypes and the line was undertaken in a&nbsp;two-year research (1997/1998 and 1998/1999) at two different locations. Significant differences among genotypes, locations and research years were established. In the first experimental year (1997/1998) there was a&nbsp;high positive correlation between nearly all components of the grain yield. The most significant correlation was found between the grain number per spike and grain yield. In the second experimental year (1998/1999) the components did not show statistically significant correlation with the grain yield. It seems that the grain yield of examined genotypes depended significantly on the grain number per spike, grain mass per spike, and agroecological conditions during the vegetation period, whereby the potential yield was determined by the interaction among genotypes, location and production year. The biggest differences among examined genotypes of winter wheat were found in the stem height and spike length.

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