The response of rate and duration of grain filling to long-term selection for yield in Italian durum wheats

2010 ◽  
Vol 61 (2) ◽  
pp. 162 ◽  
Author(s):  
Rosella Motzo ◽  
Francesco Giunta ◽  
Giovanni Pruneddu
Keyword(s):  
Grain Yield ◽  
Durum Wheat ◽  
Triticum Turgidum ◽  
Unit Area ◽  
Grain Filling ◽  
Moisture Stress ◽  
Significant Negative Correlation ◽  
Grain Number ◽  
Ambient Temperatures ◽  
Selection For

Genetic advance in durum wheat (Triticum turgidum subsp. durum) grain yield in Italy has been achieved by bringing forward flowering time, achieving a larger number of grains per unit area, and altering the pattern of senescence. The performance, in the absence of any moisture stress, of a set of 6 Italian durum wheat cultivars released over the past 100 years was compared under 4 environments and 2 nitrogen rates, to ascertain whether the changes brought about by selection for yield have also indirectly affected the rate and duration of grain filling. Grain filling lasted 35–36 days in all cultivars except ‘Ichnusa’ (39 days), although modern cultivars flowered earlier than older ones. The lack of any breeding effect on grain-filling duration also meant that the later old cultivars were not negatively affected by the higher ambient temperatures during their grain filling. The maximum rate of grain filling ranged from 2.4 to 3.3 mg/day and showed a highly significant negative correlation with the year of cultivar release (r = –0.91*). The variation in grain weight, significant but not correlated with the year of release, was associated with the rate of grain filling, which was in turn related to the grain number per unit area. A compensating variability still exists among modern Italian cultivars in both grain number and grain-filling rate, which demonstrates that durum wheat grain yield can be increased while also preserving high grain weights.

Plant population and shading studies in barley

1971 ◽  
Vol 77 (3) ◽  
pp. 445-452 ◽  
Author(s):  
R. W. Willey ◽  
R. Holliday
Keyword(s):  
Grain Yield ◽  
Dry Matter ◽  
Unit Area ◽  
Grain Filling ◽  
Crop Growth ◽  
Plant Population ◽  
Grain Number ◽  
Ear Development ◽  
Development Period ◽  
Lower Production

SUMMARYTwo barley experiments are described in which a range of plant populations were shaded during different periods of development. Shading during the ear development period caused considerable reductions in grain yield, largely by reducing the number of grains per ear. Shading during the grain-filling period caused no reduction in grain yield. It is suggested that under conditions of these experiments there was probably a potential surplus of carbohydrate available for grain filling and that grain yield was largely determined by the storage capacity of the ears. The importance of the number of grains per ear as an indicator of individual ear capacity is emphasized.The effects of plant population on grain yield and its components are also examined. It is concluded that the number of grains per ear is the component having greatest influence on the decrease in grain yield at above-optimum populations and attention is again drawn to the possible importance of ear capacity. It is argued that on an area basis the number of grains per unit area may give a good indication of ear capacity. Examination of this parameter shows a close relationship with grain yield per unit area for both the shading and population treatments. It is particularly evident that a decrease in grain yield at high populations was associated with a comparable decrease in the number of grains per unit area. It is suggested that this decrease in grain number may be due to a lower production of total dry matter during ear development rather than an unfavourable partitioning of this dry matter between the ear and the rest of the plant. This lower production of total dry matter is attributed to the crop growth rates of the higher populations having reached their peak and then having declined before the end of the ear development period. This crop growth rate pattern, through its effect on grain number per unit area, is put forward as the basic reason why, in the final crop, grain yield per unit area decreases at above-optimum populations.

Awnedness affects grain yield and kernel weight in near-isogenic lines of durum wheat

2002 ◽  
Vol 53 (12) ◽  
pp. 1285 ◽  
Author(s):  
Rosella Motzo ◽  
Francesco Giunta
Keyword(s):  
Grain Yield ◽  
Durum Wheat ◽  
Photosynthetic Capacity ◽  
Triticum Turgidum ◽  
Flag Leaf ◽  
Canopy Temperature ◽  
Leaf Size ◽  
Grain Filling ◽  
Kernel Weight ◽  
Severe Drought

The importance of awns in durum wheat (Triticum turgidum L. var. durum) has to be evaluated whenever an increase in grain yield is expected due to a greater photosynthetic capacity of the awned ear. Awned and awnless isolines of durum wheat were compared in a 3-year field trial in Sardinia (Italy). Ear and flag-leaf size, radiation interception, canopy temperature, yield, and yield components were measured.Awns increased the ear surface area from 36 to 59%, depending on their length, which ranged from 5.5 to 13.8 cm. This resulted in an average 4% more radiation intercepted by the awned ears. Canopy temperature was 0.9�C lower, on average, in the awned isolines, and was negatively correlated with kernel weight (r = –0.85**, n = 10), although consistent and marked effects of awns on canopy temperature were only observed in the long-awned lines. Awns positively affected grain yield, with an average increase of 10 and 16%, respectively, in the 2 years in which they affected kernel weight. The irrelevant effect of awns on yield in the year characterised by a severe drought was a consequence of their early desiccation.The effects of awns on grain yield and kernel weight strongly depend on the genetic background, on awn length and functionality, and on the environmental conditions during grain filling.

Variation in water use and transpiration efficiency among durum wheat genotypes grown under moisture stress and non-stress conditions

2003 ◽  
Vol 141 (1) ◽  
pp. 31-41 ◽  
Author(s):  
K. F. SOLOMON ◽  
M. T. LABUSCHAGNE
Keyword(s):  
Grain Yield ◽  
Durum Wheat ◽  
Water Use ◽  
Harvest Index ◽  
Moisture Stress ◽  
Stress Conditions ◽  
Transpiration Efficiency ◽  
High Positive Correlation ◽  
Wheat Genotypes ◽  
Selection For

Durum wheat genotypes with different responses to moisture stress were studied in a glasshouse under moisture stress and non-stress conditions to investigate differences in water use and transpiration efficiency and interrelationships among water use and transpiration efficiency and associated traits. Significantly high genotypic variability in the cumulative amount of water used before (ETba) and after (ETpa) anthesis was observed. Susceptible genotypes used higher amounts of water before anthesis and lower amounts after anthesis. In contrast, tolerant genotypes used a higher proportion of water during the post-anthesis period. Significantly high variability among the genotypes was observed for various measures of water use and transpiration efficiency, total dry matter and harvest index. Ranking of cultivars for water use efficiency based on grain yield (WUEG) and transpiration efficiency based on grain yield was consistent with ranking of cultivars for drought susceptibility indices. Drought susceptibility index was significantly but negatively correlated with harvest index, WUEG and grain yield. However, it was positively and significantly correlated with the ETba[ratio ]ETpa ratio. A high positive correlation of WUEG with harvest index and grain yield with harvest index was found. It was concluded that selection for lower ETba[ratio ]ETpa ratios up to about 0·8 could indirectly lead to improved WUEG and HI, hence improved grain yield. Selection for increased WUEG and/or grain yield would increase yield in water-limited environments.

scholarly journals Role of Nitrogen Uptake and Grain Number on the Determination of Grain Nitrogen Content in Old Durum Wheat Cultivars

Agronomy ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 42
Author(s):  
Francesco Giunta ◽  
Marina Mefleh ◽  
Giovanni Pruneddu ◽  
Rosella Motzo
Keyword(s):  
Grain Yield ◽  
Durum Wheat ◽  
N Uptake ◽  
Grain Filling ◽  
Grain Protein ◽  
Total Biomass ◽  
Wheat Cultivars ◽  
Grain Number ◽  
Protein Percentage ◽  
N Source

Old durum wheat cultivars are attracting renewed attention due to their suitability to low input agricultural systems. Fourteen old durum wheat cultivars were analyzed in two field trials to assess the effect of grain number and N absorbed and translocated by the crops on grain protein percentage. The mean grain yield was below 3 t ha−1 and strongly associated with the number of grains m−2 (GNO) (r = 0.97 ***). Grain yield displayed a low sensitivity to severe terminal stressful conditions due to the ability of the old durum wheat cultivars to maintain high grain weights despite the high temperatures and short time available for grain filling caused by their late anthesis. The N source for the growing grains was mainly dependent on pre-anthesis N uptake, which was positively associated with the total biomass produced by anthesis. The tall cultivars generally left a greater amount of N m−2 (8–15 g m−2) in their straw compared with shorter ones (5–6 g m−2). The low and variable GNO modulated the amount of N potentially available for each grain and probably limited the possibility of delivering the large N source to the grains. The large grains played a positive role in determining both grain yield (by compensating for the low GNO) and grain protein percentage, as their high grain filling rate was associated with a high N accumulation rate, and hence with a high grain N content and protein percentage.

IMPROVEMENT OF SPRING DURUM WHEAT SELECTION METHODOLOGIES UNDER CLIMATE CHANGE CONDITIONS

1970 ◽  
pp. 33-36
Author(s):  
А. I. Grabovets ◽  
V. P. Kadushkina ◽  
S. А. Kovalenko
Keyword(s):  
Grain Yield ◽  
Durum Wheat ◽  
Correlation Coefficient ◽  
Harvest Index ◽  
Unit Area ◽  
Correlation Coefficients ◽  
Chemical Mutagenesis ◽  
Main Method ◽  
The Relationship ◽  
Selection Of

With the growing aridity of the climate on the Don, it became necessary to improve the methodology for conducting the  breeding of spring durum wheat. The main method of obtaining the source material remains intraspecific step hybridization. Crossings were performed between genetically distant forms, differing in origin and required traits and properties. The use of chemical mutagenesis was a productive way to change the heredity of genotypes in terms of drought tolerance. When breeding for productivity, both in dry years of research and in favorable years, the most objective markers were identified — the size of the aerial mass, the mass of grain per plant, spike, and harvest index. The magnitude of the correlation coefficients between the yield per unit area and the elements of its structure is established. It was most closely associated with them in dry years, while in wet years it decreased. Power the correlation of the characteristics of the pair - the grain yield per square meter - the aboveground biomass averaged r = 0.73, and in dry years it was higher (0.91) than in favorable ones (0.61 - 0.70) , between the harvest and the harvest index - r = 0.81 (on average). In dry years, the correlation coefficient increased to 0.92. Research data confirms the greatest importance of the mass of grain from one ear and the plant in the formation of grain yield per unit area in both dry and wet years. In dry years, the correlation coefficient between yield and grain mass per plant was on average r = 0.80; in favorable years, r = 0.69. The relationship between yield and grain mass from the ear was greater — r = 0.84 and r = 0.82, respectively. Consequently, the breeding significance of the aboveground mass and the productivity of the ear, as a criterion for the selection of the crop, especially increases in the dry years. They were basic in the selection.

Factors Influencing the Rate and Duration of Grain Filling in Wheat

1977 ◽  
Vol 4 (5) ◽  
pp. 785 ◽  
Author(s):  
I Sofield ◽  
LT Evans ◽  
MG Cook ◽  
IF Wardlaw
Keyword(s):  
Growth Rate ◽  
Grain Yield ◽  
Grain Growth ◽  
Dry Weight ◽  
Grain Filling ◽  
Close Relation ◽  
Grain Number ◽  
Lag Period ◽  
The Difference ◽  
Leaf Photosynthetic Rate

Controlled-environment conditions were used to examine the effects of cultivar and of temperature and illuminance after anthesis on grain setting and on the duration and rate of grain growth. After an initial lag period, which did not differ greatly between cultivars, grain dry weight increased linearly under most conditions until final grain weight was approached. Growth rate per grain depended on floret position within the ear, varied between cultivars (those with larger grains at maturity having a faster rate), and increased with rise in temperature. With cultivars in which grain number per ear was markedly affected by illuminance, light had relatively little effect on growth rate per grain. With those in which grain number was less affected by illuminance, growth rate per grain was highly responsive to it, especially in the more distal florets. In both cases there was a close relation between leaf photosynthetic rate as influenced by illuminance, the rate of grain growth per ear, and final grain yield per ear. The duration of linear grain growth, on the other hand, was scarcely influenced by illuminance, but was greatly reduced as temperature rose, with pronounced effects on grain yield per ear. Cultivars differed to some extent in their duration of linear growth, but these differences accounted for less of the difference in final weight per grain than did those in rate of grain growth. Under most conditions the cessation of grain growth did not appear to be due to lack of assimilates.

scholarly journals Effects of Drought Stress on Some Agronomic and Morpho-Physiological Traits in Durum Wheat Genotypes

2020 ◽  
Vol 12 (14) ◽  
pp. 5610
Author(s):  
Alireza Pour-Aboughadareh ◽  
Reza Mohammadi ◽  
Alireza Etminan ◽  
Lia Shooshtari ◽  
Neda Maleki-Tabrizi ◽  
...  
Keyword(s):  
Drought Stress ◽  
Grain Yield ◽  
Durum Wheat ◽  
Harvest Index ◽  
Plant Biomass ◽  
Geometric Mean ◽  
Grain Filling ◽  
Tolerance Index ◽  
Wheat Genotypes ◽  
Grain Filling Period

Durum wheat performance in the Mediterranean climate is limited when water scarcity occurs before and during anthesis. The present research was performed to determine the effect of drought stress on several physiological and agro-morphological traits in 17 durum wheat genotypes under two conditions (control and drought) over two years. The results of analysis of variance indicated that the various durum wheat genotypes responded differently to drought stress. Drought stress significantly reduced the grain filling period, plant height, peduncle length, number of spikes per plot, number of grains per spike, thousand grains weight, grain yield, biomass, and harvest index in all genotypes compared to the control condition. The heatmap-based correlation analysis indicated that grain yield was positively and significantly associated with phenological characters (days to heading, days to physiological maturity, and grain filling period), as well as number of spikes per plant, biomass, and harvest index under drought conditions. The yield-based drought and susceptible indices revealed that stress tolerance index (STI), geometric mean productivity (GMP), mean productivity (MP), and harmonic mean (HM) were positively and significantly correlated with grain yields in both conditions. Based on the average of the sum of ranks across all indices and a three-dimensional plot, two genotypes (G9 and G12) along with the control variety (G1) were identified as the most tolerant genotypes. Among the investigated genotypes, the new breeding genotype G12 showed a high drought tolerance and yield performance under both conditions. Hence, this genotype can be a candidate for further multi-years and locations test as recommended for cultivation under rainfed conditions in arid and semi-arid regions.

scholarly journals Variation and Relationships among Agronomic Traits in Durum Wheat [Triticum turgidum(L.) Thell. ssp.turgidumconv.durum(Desf.) MacKey] under South Mediterranean Growth Conditions: Stepwise and Path Analyses

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Ali Mansouri ◽  
Bachir Oudjehih ◽  
Abdelkader Benbelkacem ◽  
Zine El Abidine Fellahi ◽  
Hamenna Bouzerzour
Keyword(s):  
Grain Yield ◽  
Durum Wheat ◽  
Harvest Index ◽  
Agronomic Traits ◽  
Triticum Turgidum ◽  
Canopy Temperature ◽  
Growth Conditions ◽  
Path Analyses ◽  
Spike Number ◽  
The One

Relationships among agronomic traits and grain yield were investigated in 56 genotypes of durum wheat (Triticum durumDesf.). The results indicated the presence of sufficient variability nearly for all measured traits. Heritability and expected genetic gain varied among traits. Aboveground biomass, harvest index, and spike number were the most grain yield-influencing traits. Early genotypes showed above-average grain and biological yields, spike number, and lower canopy temperature. Assessed genotypes were clustered into three groups which differed mainly for biological, economical, straw, and grain yields, on the one hand, and plant height, chlorophyll content, and canopy temperature, on the other hand. Selection for direct use from clusters carrying best combinations of yield-related traits and crosses to be made between genotypes belonging to contrasted clusters were suggested to generate more variability. Selection preferentially for spike number, biological yield, harvest index, and canopy temperature to accumulate favorable alleles in the selected entries for future uses is suggested.

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