The predictive value of parental, F1 and early generation hill-plot testing for yield among rapidly advanced hexaploid triticales

1994 ◽  
Vol 45 (1) ◽  
pp. 51 ◽  
Author(s):  
RM Trethowan ◽  
NL Darvey

Rapid generation turnover techniques were used to identify parental, single cross or backcross populations with yield potential in triticale. Both complete (complete rye genome) and substituted (2D/2R substitution) triticale karyotypes were crossed. Temperature and light controlled greenhouses, immature seed germination, embryo culture and off season nurseries were used to advance three generations in 11 months. Due to seed limitations in the early generations, hill-plots were used to measure total dry matter, grain yield and harvest index. Mid-parent, F2 and F3 hill-plot yield was equivalent to or better than dry matter and harvest index for the prediction of F4 hill-plot yield. Both hill-plot yield (r = 0.54) and dry matter (r = 0-51) were significantly correlated (P < 0.01) with large plot grain yield at the same site in the same year. The best predictors of F4 hill-plot yield were mid-parent, F2 and F3 mean hill-plot yield with phenotypic correlations of 0- 26� 0.17, 0.3510 -03 and 0.44� 0.06 respectively. The F1 (r = -0.02�0.12) provided no association with F4 hill-plot yield, reflecting the high average heterosis for yield (22%) observed in this material. Mid-parent, F2, F3 and F4 dry matter and yield means were significantly lower in inter-karyotypic crosses than intra-karyotypic crosses; however, the relationship between generations appeared to be independent of karyotype. A response to visual selection of individual spikes from hill-plots was obtained at two sites for dry matter and grain yield.

1990 ◽  
Vol 70 (4) ◽  
pp. 965-977 ◽  
Author(s):  
J. M. CLARKE ◽  
C. A. CAMPBELL ◽  
H. W. CUTFORTH ◽  
R. M. DePAUW ◽  
G. E. WINKLEMAN

A field study was carried out in four environments to determine the effects of available water and cultivar on N and P uptake, translocation, and utilization efficiency of wheat (Triticum spp.) cultivars with varying grain yield potential and protein concentration. Two common wheat (T. aestivum L.) cultivars, Neepawa and HY320, and two durum (T. turgidum L. var. durum) cultivars, DT367 and Wakooma, were studied. HY320 and DT367 had higher grain yield potentials and lower protein concentrations than Neepawa and Wakooma. Total plant N and P uptake was proportional to available water, and was strongly associated with dry matter accumulation. From 67 to 102% of plant N and 64–100% of P present at harvest had been accumulated by anthesis. Postanthesis uptake of N and P was greater under moist than under dry environments. There were few cultivar differences in uptake of N or P, and any differences observed were related to variations in plant dry matter. Nitrogen harvest index ranged from 71 to 85% and P harvest index ranged from 81 to 93%. Both indices responded to environment in the same way as grain harvest index; there were no cultivar differences for either N or P harvest index. From 59 to 79% of N and 75 to 87% of P present in vegetative tissues at anthesis was translocated to the grain; translocation did not vary among cultivars. The efficiency of utilization of N and P in production of harvest biomass and grain was directly proportional to water availability and was greater in the high yield cultivars HY320 and DT367 than in Neepawa and Wakooma. There was no evidence that selection for N uptake, translocation, or utilization efficiency would be useful in wheat breeding.Key words: Triticum aestivum L., T. turgidum L. var. durum, nitrogen harvest index, phosphorus harvest index


1993 ◽  
Vol 29 (1) ◽  
pp. 77-86 ◽  
Author(s):  
P. Q. Craufurd ◽  
J. M. Peacock

SummaryThree early and four later flowering lines of sorghum were subjected to three drought stress treatments (early, late and early plus late stress) in the field during the dry season at Hyderabad in India. Mean diurnal temperature and evaporation rate were uniformly high throughout the experiment. The late and early plus late stress conditions were severe, while the early stress was mild.Grain yield was affected by both the timing and the severity of the stress. The largest reduction (87%) in grain yield resulted from stress imposed during booting and flowering (late stress) in the early flowering lines; the same stress treatment on vegetative plants had no effect on grain yield. Increasing the duration of severe stress on vegetative plants (early plus late stress) reduced grain yield by 50–60%.Grain yield was strongly and positively correlated with the number of grains m-2. Variation in grain yield was associated with variation in total dry matter rather than with harvest index, which was only reduced when stress occurred at flowering. Treatment effects on thermal growth rates (g m-2 °Cd-1) during the phase from booting to flowering confirmed that growth during this phase is the major determinant of yield potential (number of grains). The importance of phonology in research into drought resistance is discussed.


1996 ◽  
Vol 76 (4) ◽  
pp. 757-761 ◽  
Author(s):  
D. E. Falk ◽  
E. Reinbergs ◽  
B. S. Chhina ◽  
D. E. Mather

Seven selected doubled haploid lines, from each of three cycles (C0, C1, C2) of a diallel recurrent selection program, the seven original parents and two check cultivars were evaluated in replicated hill and row plots at two locations in Ontario in 1988 and 1989. Comparison of hill and row plots using means ranges, coefficient of variation, repeatability and correlations among traits indicated that grain yield, days to heading plant height and powdery mildew resistance could be evaluated with similar accuracy and precision using either of the methods. Regression of row plot yield on hill plot yield was positive and highly significant showing a strong relationship between the two plot types for grain yield. Selection efficiency in hill plots was high for all the traits. The percentage of lines with similar performance for yield in both the plot types was high. The hill plot method appears to be a useful technique for evaluating homozygous lines for yield and other agronomic traits in a doubled haploid recurrent selection program in six-row barley. Key words:Hordeum vulgare L., barley, breeding methods, yield, powdery mildew, doubled haploid, recurrent selection


1991 ◽  
Vol 18 (1) ◽  
pp. 53 ◽  
Author(s):  
PC Pheloung ◽  
KHM Siddique

Field experiments were conducted in the eastern wheat belt of Western Australia in a dry year with and without irrigation (1987) and in a wet year (1988), comparing three cultivars of wheat differing in height and yield potential. The aim of the study was to determine the contribution of remobilisable stem dry matter to grain dry matter under different water regimes in old and modern wheats. Stem non-structural carbohydrate was labelled with 14C 1 day after anthesis and the activity and weight of this pool and the grain was measured at 2, 18 and 58 days after anthesis. Gutha and Kulin, modern tall and semi-dwarf cultivars respectively, yielded higher than Gamenya, a tall older cultivar in all conditions, but the percentage reduction in yield under water stress was greater for the modern cultivars (41, 34 and 23%). In the grain of Gamenya, the increase in 14C activity after the initial labelling was highest under water stress. Generally, loss of 14C activity from the non-structural stem dry matter was less than the increase in grain activity under water stress but similar to or greater than grain activity increase under well watered conditions. Averaged over environments and cultivars, non-structural dry matter stored in the stem contributed at least 20% of the grain dry matter.


1988 ◽  
Vol 68 (2) ◽  
pp. 311-322 ◽  
Author(s):  
PATRICK M. McMULLAN ◽  
PETER B. E. McVETTY ◽  
AILEEN A. URQUHART

Dry matter and nitrogen (nitrate and reduced) accumulation and redistribution in four different spring wheat (Triticum aestivum L.) genotypes grown at field density were studied on a plant part and whole plant basis over the growing season for 2 yr. The four cultivars displayed significant differences in plant part and total plant dry matter, harvest index, nitrogen content, nitrogen concentration, nitrogen harvest index and nitrogen translocated values at most sample dates in both years. Grain yield was highly correlated with dry matter accumulation (r = 0.88**), while grain nitrogen content was highly correlated with plant nitrogen content (r = 0.95**). Nitrogen harvest index and plant nitrogen content were correlated at anthesis (r = 0.61**), while, as a consequence of this, the amount of nitrogen translocated was highly correlated with plant nitrogen content at anthesis (r = 0.87**). Nitrogen harvest index and harvest index were highly correlated (r = 0.83**), indicating that they may be related processes. Since plant dry matter and plant nitrogen content were not significantly correlated, it should be possible to select simultaneously for these traits to effect grain yield and grain nitrogen content increases on a per-plant basis. Further research will have to be done to determine how these changes will relate to grain nitrogen concentrations and grain yield per unit area.Key words: Wheat, dry matter, nitrogen, yield, protein, Triticum aestivum L.


2007 ◽  
Vol 58 (1) ◽  
pp. 21 ◽  
Author(s):  
Heping Zhang ◽  
Neil C. Turner ◽  
Michael L. Poole ◽  
Senthold Asseng

The growth and yield of spring wheat (Triticum aestivum L.) were examined to determine the actual and potential yields of wheat at a site in the high rainfall zone (HRZ) of south-western Australia. Spring wheat achieved yields of 5.5−5.9 t/ha in 2001 and 2003 when subsurface waterlogging was absent or minimal. These yields were close to the estimated potential, indicating that a high yield potential is achievable. In 2002 when subsurface waterlogging occurred early in the growing season, the yield of spring wheat was 40% lower than the estimated potential. The yield of wheat was significantly correlated with the number of ears per m2 (r2 = 0.81) and dry matter at anthesis (r2 = 0.73). To achieve 5–6 t/ha of yield of wheat in the HRZ, 450–550 ears per m2 and 10–11 t/ha dry matter at anthesis should be targetted. Attaining such a level of dry matter at anthesis did not have a negative effect on dry-matter accumulation during the post-anthesis period. The harvest index (0.36−0.38) of spring wheat was comparable with that in drier parts of south-western Australia, but relatively low given the high rainfall and the long growing season. This relatively low harvest index indicates that the selected cultivar bred for the low- and medium-rainfall zone in this study, when grown in the HRZ, may have genetic limitations in sink capacity arising from the low grain number per ear. We suggest that the yield of wheat in the HRZ may be increased further by increasing the sink capacity by increasing the number of grains per ear.


2003 ◽  
Vol 140 (4) ◽  
pp. 395-407 ◽  
Author(s):  
R. E. RUSKE ◽  
M. J. GOODING ◽  
S. A. JONES

Field experiments were conducted over 3 years to assess the effect of a triazole fungicide programme, and additions of strobilurin fungicides to it, on nitrogen uptake, accumulation and partitioning in a range of winter wheat cultivars. Commensurate with delayed senescence, fungicide programmes, particularly when including strobilurins, improved grain yield through improvements in both crop biomass and harvest index, although the relationship with green area duration of the flag leaf (GFLAD) depended on year and in some cases, cultivar. In all years fungicide treatments significantly increased the amount of nitrogen in the above-ground biomass, the amount of nitrogen in the grain and the nitrogen harvest index. All these effects could be linearly related to the fungicide effect on GFLAD. These relationships occasionally interacted with cultivar but there was no evidence that fungicide mode of action affected the relationship between GFLAD and yield of nitrogen in the grain. Fungicide treatments significantly reduced the amount of soil mineral N at harvest and when severe disease had been controlled, the net remobilization of N from the vegetation to the grain after anthesis. Fungicide maintained the filling of grain with both dry matter and nitrogen. The proportionate accumulation of nitrogen in the grain was later than that of dry matter and this difference was greater when fungicide had been applied. Effects of fungicide on grain protein concentration and its relationship with GFLAD were inconsistent over year and cultivar. There were several instances where grain protein concentration was unaffected despite large (1·5 t/ha) increases in grain yield following fungicide use. Dilution of grain protein concentration following fungicide use, when it did occur, was small compared with what would be predicted by adoption of other yield increasing techniques such as the selection of high yielding cultivars (based on currently available cultivars) or by growing wheat in favourable climates.


1988 ◽  
Vol 68 (4) ◽  
pp. 983-993 ◽  
Author(s):  
PATRICK M. McMULLAN ◽  
PETER B. E. McVETTY ◽  
AILEEN A. URQUHART

Dry matter and nitrogen (nitrate and reduced) accumulation and redistribution in four different spring oat (Avena sativa L.) genotypes grown at commercial field density were studied on a plant part and whole plant basis over the growing season for 2 yr. The four cultivars displayed significant differences in plant part and total plant dry matter, harvest index, nitrogen content, nitrogen concentration, nitrogen harvest index, and nitrogen translocated values at most sample dates in both years. Grain yield per plant was correlated with dry matter accumulation (r = 0.80*). Harvest index was highly correlated with grain yield per plant (r = 0.88**). Grain nitrogen content was highly correlated with plant nitrogen content (r = 0.94**). Nitrogen harvest index and harvest index were highly correlated (r = 0.86**), indicating that they may be related processes. Since plant dry matter and plant nitrogen content were not significantly correlated, it should be possible to select simultaneously for these traits to effect grain yield and grain nitrogen content increases on a per plant basis. Further research will have to be done to determine how these changes will relate to grain nitrogen concentrations and grain yield per unit area.Key words: Avena sativa L., oat, dry matter, nitrogen, yield, protein


Weed Science ◽  
1996 ◽  
Vol 44 (3) ◽  
pp. 634-639 ◽  
Author(s):  
Deirdre Lemerle ◽  
Birgitte Verbeek ◽  
Neil E. Coombes

The influence of wheat variety on the dose-response of annual ryegrass to diclofop-methyl (POST) was examined in the field in 1992 and 1993 in southern New South Wales, Australia. The aim was to determine if planting a strongly competitive variety of wheat improved control of annual ryegrass at reduced doses of diclofop-methyl. Suppression of ryegrass was dependent on herbicide dose, season, and wheat variety. In the absence of herbicide, dry matter (DM) production of annual ryegrass at 300 plants m−2at anthesis was 500 g ha−1with Dollarbird and Katunga compared to 1000 g ha−1with Rosella or Shrike in 1992. In 1993, DM was approximately 150 g ha−1with Dollarbird or Katunga, and 350 g ha−1with Shrike or Rosella. Ryegrass DM was reduced by diclofop-methyl to a greater extent, relative to the weedy unsprayed controls, with less competitive varieties Rosella and Shrike than with the more competitive Dollarbird or Katunga. Diclofop-methyl at 0.28 kg a.i. ha−1reduced DM of ryegrass growing with Katunga to less than 100 g m−2in 1992, compared to more than 200 g m2with the other varieties. In 1993, diclofop-methyl was more effective on ryegrass, and the same dose reduced ryegrass DM to almost zero in all varieties. Grain yields in unsprayed weedy controls of Dollarbird and Katunga were reduced approximately 20% by annual ryegrass compared with yields achieved with herbicides in both years. Yields of Rosella and Shrike in the unsprayed controls were reduced about 40% in 1992 and 60% in 1993. Only small increases in grain yields of all varieties occurred from diclofop-methyl doses above 0.13 kg a.i. ha−1. Poorly competitive varieties were dependent on herbicides to achieve grain yield potential and had a greater risk of weed survival when herbicide efficacy was reduced. In contrast, strongly competitive varieties, likely to retard build-up of weed seed in the soil, are less dependent on herbicides to achieve grain yield potential, and therefore result in reduced weed control cost.


1987 ◽  
Vol 108 (2) ◽  
pp. 469-477 ◽  
Author(s):  
S. R. Waddington ◽  
M. Osmanzai ◽  
M. Yoshida ◽  
J. K. Ransom

SummaryTwo trials designed to measure progress in the yield of durum wheat cultivars released in Mexico by the Institute Nacional de Investigaciones Agrícolas over the period 1960–84 were grown in the Yaqui Valley, Sonora, Mexico, during the 1983–4 and 1984–5 cropping seasons. The trials compared grain yield, above-ground biomass, harvest index (ratio of dry grain yield to dry above-ground biomass), yield components, grain-growth rates and phenological characters for eight key cultivars and the modern advanced line, Carcomun ‘S’, when grown at a high level of agronomic inputs and management.The grain yield of durum wheat was estimated to have risen for 25 years of breeding from 3·70 to 8·40 t/ha. The estimated average annual rates of increase in grain yield for the periods 1960–71 and 1971–85 were 251 and 121 kg/ha respectively. Grain yield improvements were based on a linear increase in the number of grains/m2 over the 25-year period, the result of more grains per spikelet. An improved above-ground biomass at maturity was a feature of the two modern genotypes, Altar 84 and Carcomun ‘S’. Harvest index increased with each new cultivar up to the release of Mexicali 75 in 1975, but thereafter the higher grain yields achieved with the modern genotypes were not associated with a higher harvest index. Thousand-grain weight remained steady for the released cultivars but fell slightly for the advanced line Carcomun ‘S’. Improvements in yield were not associated with a longer cropping cycle.It is concluded that a breeding strategy combining selection for morphological characters thought to confer high yield potential, such as a more erect leaf posture and high number of grains per spikelet, with selection for grain yield per se has been successful in improving the grain yield of durum wheats adapted to north-west Mexico. Improvements have come not only in the size of the grain sink and the efficiency of assimilate partition to grain but also in the biomass produced above ground.


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