GENOTYPE × ENVIRONMENT INTERACTIONS IN SMOOTH BROMEGRASS. II. MORPHOLOGICAL CHARACTERS AND THEIR ASSOCIATIONS WITH FORAGE YIELD

1979 ◽  
Vol 21 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Wai-Koon Tan ◽  
Geok-Yong Tan ◽  
P. D. Walton

The parents and progenies of a 7 × 7 diallel cross of smooth bromegrass (Bromus inermis Leyss.) were evaluated for the genetic variability of some morphological characters and their associations with yield, at four locations in Alberta in 1976 and 1977. Locations, years and their interactions were highly significant for all characters and were subsequently treated as eight environments. The partition of the genotypic variance into general combining ability (GCA) and specific combining ability (SCA) showed that for all morphological characters, GCA was more important than SCA, indicating the importance of additive genetic effects. The genotype × environment (GE) interactions were highly significant. Variation accounted for by GCA was generally higher than the interaction effects of GCA and SCA with environments. Phenotypic and genotypic correlation coefficients revealed that both tiller density and height were significantly correlated with yields. Path coefficient analysis also showed that tiller density, followed by leaf area and tiller dry weight, exerted the greatest direct influence on yield. Selection for large leaf area and more and heavier tillers per unit area would simultaneously increase bromegrass productivity. Furthermore, selection should be based on multi-year and multi-location tests.

2007 ◽  
Vol 58 (11) ◽  
pp. 1100 ◽  
Author(s):  
E. Piano ◽  
P. Annicchiarico ◽  
M. Romani ◽  
L. Pecetti

Finding the optimal parent number for synthetic varieties has a crucial importance in forage breeding. The objective of this work was exploring this number for Mediterranean tall fescue selected for forage yield. The general (GCA) and specific (SCA) combining ability of parents, and their effects on the performance and the inbreeding depression of synthetics, were also assessed. The full-sib families from the diallel cross of 20 genotypes chosen from well performing populations were evaluated for fresh biomass over 13 harvests in Sanluri (Sardinia, Italy). The Syn 1 and Syn 2 of 15 synthetics varying in parent number (4, 8, 12, 16 or 20) and, within same number, in mean GCA of parents were evaluated for dry matter yield over 11 harvests in Lodi (northern Italy) in a greenhouse simulating the temperature pattern of a Mediterranean environment. The yield responses of Syn 2 synthetics with 2 to 20 parents with highest mean GCA were predicted from yield values of S1 and F1 progenies, also evaluated in Lodi. The variance of GCA effects was almost 2-fold larger than that of SCA effects. The observed vigour loss from Syn 1 to Syn 2 of the 4-parent synthetics (−6%) tended to be greater than those of higher parent number groups. The 4-parent synthetics with larger SCA effects tended to greater inbreeding depression. The comparison among synthetics with different parent number and highest GCA of their parents indicated the superiority of the 4-parent synthetic over any other in both generations (P < 0.05). The predicted yield response was maximised by the 3-parent synthetic. The results and other considerations suggest adoption of 4- to 6-parent synthetics.


1979 ◽  
Vol 21 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Wai-Koon Tan ◽  
Geok-Yong Tan ◽  
P. D. Walton

Twenty-one progenies and the parents of a 7 × 7 half diallel cross of smooth bromegrass (Bromus inermis Leyss.) were evaluated at four locations in Alberta in each of two years, for genetic variation and genetic by environment interactions in the expression of their yield potentials. Years, locations and their interactions were highly significant in the combined analysis of variance. Combining ability analysis revealed that general combining ability (GCA) and specific combining ability (SCA) were both important in the expression of yield, including spring, fall and annual yield, whereas GCA was more important than SCA for yield per area. Although the genotype × environment interactions were all highly significant, variation accounted for by combining ability effects was generally higher than the interaction effects of GCA and SCA respectively, with environments. High average GCA effects for spring, fall and annual yield were demonstrated for the clones UA5, UA9 and B42. These together with the high average SCA effects suggested that the three clones could be included in a synthetic to develop high yielding cultivars. The results suggested that recurrent selections involving multi-location and multi-year testing seems necessary in breeding for high yielding bromegrass cultivars in Alberta.


2017 ◽  
Vol 6 (2) ◽  
pp. 1531 ◽  
Author(s):  
Prajjwal Dubey ◽  
Raghubanshi A. S. ◽  
Anil K. Dwivedi*

A range of leaf attributes was measured for 17 herbaceous species in four contrasting habitats fortnightly from July to September during 2996-2007. All herbaceous vegetation in 5 randomly located plots within each of four sites were clipped at ground level and analyzed fortnightly. Leaf area was recorded by the leaf area meter (Systronics; Leaf area meter- 211). Fresh leaves were dried at 80o C for 48 hr to estimate their dry weight. Specific Leaf Area (SLA) was determined as ratio of leaf area to leaf dry weight. Leaf nitrogen was measured by Kjeldahl method and phosphorus by phosphomolybdic blue colorimetric method. The obtained values were subjected to Two- tailed Pearson correlation coefficients using SPSS (2004 ver. 13) package. SLA, leaf nitrogen, leaf phosphorus and photosynthetic rate show positive relationship with each other.


1967 ◽  
Vol 47 (4) ◽  
pp. 359-365 ◽  
Author(s):  
H. D. Voldeng ◽  
G. M. Simpson

Shading treatments with a high- and a low-yielding line of wheat indicated that the ear and flag leaf contributed the major portion of grain dry weight. Correlation coefficients calculated between flag-leaf area and grain yield, and ear area and grain yield, from tillers within seven lines of wheat ranged from + 0.54 to + 0.90. The combination of a large flag leaf plus a large ear area showed promise as an index for selecting higher yielding individuals from a mixture of genotypes.


1969 ◽  
Vol 49 (5) ◽  
pp. 587-596 ◽  
Author(s):  
P. D. Walton

Records from seven spring wheats in a diallel cross showed that flag-leaf lamina area, extrusion of the head from the leaf sheath, head length and yield were all controlled by minor genes. Additive gene action and general combining ability were shown to be important genetic factors for all characters studied. Partial dominance was present for yield, flag-leaf area and head length. There was evidence that over-dominance played a part in the inheritance of extrusion. The genetic factors which controlled the expression of small leaf size showed dominance over those for large leaves and appeared to be distributed over all chromosomes. Increased extrusion and large flag-leaf area were both shown to be associated with high yield.


1968 ◽  
Vol 19 (3) ◽  
pp. 411 ◽  
Author(s):  
JG Wutoh ◽  
WM Hutton ◽  
AJ Pritchard

A diallel cross of five accessions was used to estimate general and specific combining ability for nine traits in Glycine javanica L. Variation due to both general and specific combining ability was highly significant but the general combining ability component of variance was larger than the specific combining ability component for flowering time, maturity date, and seed weight. For yield, stolon length, stolon number, and percentage of stolons rooted the specific combining ability component was the larger. The cultivar Tinaroo had a high general combining ability and a low specific combining ability for most traits associated with forage yield and should be a valuable parent in future breeding programmes. Negative genetic correlations between yield and some traits associated with stolon development indicate that it may not be possible to produce a variety with all desirable characters from a breeding programme based on the five accessions used.


2020 ◽  
Vol 48 (1) ◽  
pp. 83-88
Author(s):  
Agung Wahyu Susilo ◽  
Sobir ◽  
Desta Wirnas ◽  
Adinda Wuriandani

Seedling is often used as planting material and rootstock for clonal propagation in cocoa. Seedling as cocoa planting material came form superior parents or crosses of superior parents. The research aimed to estimate the genetic components of cocoa morphological characters using the North Carolina II mating design. Three female parent genotypes, namely KW 516, Sulawesi 3, and TSH 858, were crossed with two male parent genotypes, namely ICCRI 09 and Scavina 6. Observed variables consisted of plant height, stem diameter, number of leaves, leaf area, root length, root volume, shoot fresh and dry weight, root fresh and dry weight, root:shoot ratio at 16 weeks after showing. General combining ability (GCA) value showed Sulawesi 3 as the best female parent, and Scavina 6 as the best male parent. Specific combining ability (SCA) values showed TSH 858 x Scavina 6, KW 516 x ICCRI 09, and Sulawesi 3 x ICCRI 09 as the best crosses. Sulawesi 3 x ICCRI 09 seedlings had good vigor and met the criteria for transplanting. Cocoa morphological characters were affected by dominant gene action except for root volume. Keywords: seedling, North Carolina II, general combining ability, specific combining ability


HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 785E-785
Author(s):  
Abdullah A. Alsadon

`Lincoln' and `Rondo' pea cultivars (Pisum sativum L. subsp. hortense) were planted at early, midseason, and late dates during 1989–90 and 1990–91 growing seasons. Plant growth analysis data were collected via weekly harvests throughout the growing season. Plant height, leaf area, and shoot dry weight were measured, and LAI, SLA, and SLW were also determined. Derived growth quantities such as RGR, NAR, and CGR were calculated. `Rondo' plants were taller, larger in leaf area, had more vegetative and dry weight, and were earlier in flowering than `Lincoln' plants. Leaf area was not significantly affected by planting date. Optimum LAI was obtained between harvests 7 and 9, which coincides with the time of highest values of NAR and CGR. Significant correlation coefficients were obtained between growth attributes in both seasons, and, in most cases, for all planting dates.


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