Effect of the number of parents and their combining ability on the performance of synthetic varieties in tall fescue

2007 ◽  
Vol 58 (11) ◽  
pp. 1100 ◽  
Author(s):  
E. Piano ◽  
P. Annicchiarico ◽  
M. Romani ◽  
L. Pecetti
Keyword(s):  
Inbreeding Depression ◽  
Tall Fescue ◽  
Combining Ability ◽  
Diallel Cross ◽  
Forage Yield ◽  
Yield Response ◽  
Temperature Pattern ◽  
Synthetic Varieties ◽  
Yield Values ◽  
Yield Responses

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.

Combining ability in Glycine javanica

1968 ◽  
Vol 19 (3) ◽  
pp. 411 ◽  
Author(s):  
JG Wutoh ◽  
WM Hutton ◽  
AJ Pritchard
Keyword(s):  
Combining Ability ◽  
Genetic Correlations ◽  
Diallel Cross ◽  
General Combining Ability ◽  
Specific Combining Ability ◽  
Forage Yield ◽  
Maturity Date ◽  
Stolon Length ◽  
Breeding Programmes ◽  
Stolon Development

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.

QUANTITATIVE GENETIC NATURE OF VEGETATIVE GROWTH IN ALFALFA

1971 ◽  
Vol 13 (1) ◽  
pp. 75-80 ◽  
Author(s):  
S. M. Singh ◽  
K. Lesins
Keyword(s):  
Combining Ability ◽  
Vegetative Growth ◽  
Genetic Factors ◽  
Diallel Cross ◽  
Specific Combining Ability ◽  
Forage Yield ◽  
High Yield ◽  
Quantitative Genetic ◽  
Diallel Crossing ◽  
Nonallelic Interactions

Seven selected clones of cultivated alfalfa, superior in forage yield, were used in the complete diallel crossing system. The crosses were made after complete emasculation of the flowers and the progenies, single planted in the field, were studied for vegetative growth at various stages for 3 years. The data was subjected to Griffing's (1956) method of diallel cross analysis and it was noted that though the general and specific combining ability variances for all these traits were significant, the genetic factors responsible for the specific combining ability, namely allelic and nonallelic interactions, were more prominent. This could be due to the fact that the material was subjected to several selection cycles for high yield. Similar conclusions were also derived from the heritability studies for growth during the year of establishment (1968), growth in spring and fall, and total vegetative yield in 1969 and 1970. In the light of the above genetic estimates, it may be proposed that additional gain in vegetative growth might be obtained by using these clones in the hybrid combinations.

Effect of nitrogen fertilizer residues on the response of irrigated bromegrass to fertilizer nitrogen

1995 ◽  
Vol 75 (2) ◽  
pp. 381-386
Author(s):  
A. J. Leyshon ◽  
C. A. Campbell
Keyword(s):  
N Fertilizer ◽  
Forage Yield ◽  
Residual Effects ◽  
Organic N ◽  
Yield Response ◽  
Fertilizer N ◽  
Response Curves ◽  
Yield Responses ◽  
Moisture Conditions ◽  
N Rates

Two nitrogen (N) fertilizer response trials were superimposed, in 2 consecutive years, on a set of large plots of irrigated bromegrass (Bromus inermis Leyss.) that had been fertilized with different rates of fertilizer N up to 200 kg ha−1 for the previous 9 and 10 yr, respectively. During those years, forage dry matter responded in direct proportion to fertilizer N rate. In the subsequent two trials we determined the residual effects of the prior fertilizer treatments on the response of bromegrass to new applications of N fertilizer, and the N rate required to achieve maximum yields. The yield response of the bromegrass to the applied N was a function of prior fertilizer history and the moisture conditions. In the first trial, under good moisture conditions, the previously unfertilized plots had maximum yields at a N rate of 382 kg N ha−1; yields declined at higher rates. Responses of previously fertilized plots to additional N were linear. The y-intercepts (where no N was applied) were higher for plots that had been fertilized at higher N rates in the initial 9-yr study while the slopes of the yield responses were less steep. In contrast, in the second trial, conducted in a year when irrigation water was restricted, all forage yield responses to N fertilizer were curvilinear, Y-intercepts were again higher on plots that had been fertilized at higher N rates in previous years. In this case, however, the slopes of the N responses became progressively steeper with increasing N rate while increasingly larger quadratic coefficients resulted in maximum yields being attained at progressively lower N rates. Nevertheless, maximum yields were higher than those of the previously unfertilized plots. Changes in the response curves were attributed to alterations in the soil organic N and to a lesser extent, to changes in the capability of the bromegrass to respond to fertilizer N. Soil tests found no carry-over of fertilizer N as residual inorganic N but the initial potential rate of mineralization (N0k) reflected changes in the quality of soil organic matter influencing the response to N fertilizer applications. The results suggest the need for soil testing laboratories to take into account the prior fertilizer history of the grass stand when developing recommended N fertilizer rates for irrigated bromegrass. Key words: Bromegrass, N fertilization, residual N, mineralizable N

General and specific combining ability for forage yield in lucerne (Medicago sativa)

1965 ◽  
Vol 16 (3) ◽  
pp. 293 ◽  
Author(s):  
H Daday
Keyword(s):  
Combining Ability ◽  
Diallel Cross ◽  
Forage Yield ◽  
Forage Production ◽  
Family Selection ◽  
Combining Ability Analysis ◽  
Positive Correlations ◽  
Spring Yield ◽  
Forage Yields ◽  
Additive Genes

The genetic control of forage yields was investigated by a combining ability analysis based on a diallel cross made up of the hybrids between nine genotypes of lucerne. Summer forage yield was found to be controlled by additive and non-additive genes, and winter yield mainly by additive genes. General combining abilities differed markedly between genotypes for both summer and winter yields, and the correlation coefficient between summer and winter yields was high (0.89).Selected F2 and F3 progenies from crosses between Du Puits, Hairy Peruvian, and African cultivars substantially exceeded parental values for summer, winter, and spring forage production under row-sward conditions. There were positive correlations between summer, winter, and spring productivity in one of the two F2 experiments and in spaced F3 plants. Heritability estiniates for summer and winter yield ranged from 22 to 28%, and for spring yield, from 14 to 18%. On the basis of the estimated genetic parameters, yield increases should be obtained by either family selection or heterosis breeding.

HYBRID VIGOR AND GENE ACTION IN A SIX-PARENT DIALLEL CROSS OF SOFT WINTER WHEAT

1971 ◽  
Vol 13 (1) ◽  
pp. 131-137 ◽  
Author(s):  
M. J. Bitzer ◽  
F. L. Patterson ◽  
W. E. Nyquist
Keyword(s):  
Winter Wheat ◽  
Plant Height ◽  
Combining Ability ◽  
Diallel Cross ◽  
Kernel Weight ◽  
Hybrid Vigor ◽  
Yield Response ◽  
Partial Dominance ◽  
Graphic Analysis ◽  
Soft Winter Wheat

Six soft winter wheat lines were crossed in a diallel fashion and data were obtained from the parents and F1 hybrid generation over two years. The mean squares for year by genotype interaction were significant for most measured characters indicating that the genotypes responded somewhat differently each year. The yield response of the F1 generation hybrids ranged from −0.7 to 28.1% with 13 of 15 F1 hybrids above the higher parent; however, none was significantly higher.Combining ability analyses were performed on the F1 hybrids, and mean squares for general combining ability were significant for earliness, plant height, and kernels per spike. No significant mean squares for specific combining ability were detected. Monon was the best general combiner for both number of spikes and yield, and Gaines was a good general combiner for kernels per spike. The Jinks and Hayman (Vr, Wr) graphic analysis indicated that plant height, kernel weight, and number of spikes were controlled by some partial dominance and yield by apparent overdominance.

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
Keyword(s):  
Leaf Area ◽  
Combining Ability ◽  
Correlation Coefficients ◽  
Diallel Cross ◽  
Dry Weight ◽  
Morphological Characters ◽  
Forage Yield ◽  
Path Coefficient ◽  
Smooth Bromegrass ◽  
Tiller Density

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.

Heterosis, inbreeding depression and combining abilities in a five-parent diallel of six-row barley

1976 ◽  
Vol 86 (3) ◽  
pp. 537-542 ◽  
Author(s):  
H. G. Nasr ◽  
W. Khayrallah
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Inbreeding Depression ◽  
Combining Ability ◽  
Diallel Cross ◽  
General Combining Ability ◽  
Kernel Weight ◽  
Specific Combining Ability ◽  
Combining Abilities ◽  
Good Yielding

SummaryThe F1 and F2 generations of a diallel cross of six-row barley involving the parents, Beecher, Athenais, Atlas 46, 3130-4564-3, and 3130-864-4 were studied and heterosis, inbreeding depression, and combining abilities were measured for grain yield, number of tillers per plant, number of kernels per plant, kernel weight, and plant height. Significant heterosis was detected for grain yield in two of the ten crosses, for number of tillers per plant in one cross, for number of kernels per plant in two crosses, for plant height in three crosses, and for kernel weight in none of the crosses. The inbreeding depression of the F2 generation was present in most cases but significantly so in a few. Atlas 46 x 3130-4564-3 exhibited inbreeding depression for grain yield, number of kernels per plant, and plant height.The general combining ability (GCA) mean squares of both generations were significant for all characters studied except number of kernels per plant in the F1 generation. The specific combining ability (SCA) mean squares were significant for only plant height in the F1 generation and all characters studied except number of tillers per plant in the F2 generation.The GCA effects indicated that Beecher and Athenais are good general combiners for grain yield and its components. The latter parent produced good yielding hybrids with slightly shorter plants than the remaining hybrids.The SCA effects revealed that Athenais × 3130-4564-3, Athenais × 3130-864-4, and Beecher × Atlas 46 seem good specific combinations for high grain yield. Also, the former two crosses tend to produce shorter plants.

COMBINING ABILITY FOR INHERITANCE OF ECONOMIC TRAITS IN OPIUM POPPY (Papaver somniferum L.)

2011 ◽  
Vol 24 (2) ◽  
pp. 01-08
Author(s):  
B. Kumar ◽  
N. K. Patra
Keyword(s):  
Combining Ability ◽  
Diallel Cross ◽  
Papaver Somniferum ◽  
Opium Poppy ◽  
Economic Traits ◽  
Degree Of Dominance ◽  
Parental Material ◽  
The Mean ◽  
Per Se ◽  
Important Medicinal Plant

Opium poppy (Papaver somniferum L.) is an important medicinal plant produces more than 80 alkaloids obtained from the capsules and straw of the plant. The estimate of combining ability gives an indication of the genetic behaviour of the parental material. It is therefore, desirable to select the parents for hybridization on the basis of their per se performance and combining ability effects. The F1, F2 and their reciprocals of an eight parent diallel cross in opium poppy were studied for combining ability of seven economic traits. The mean sum of squares due to GCA, SCA and reciprocals were significant for all the traits. The magnitude of GCA variances were invariably higher than those of SCA and thus indicating the preponderance of non-additive genetic variances, which was further affirmed by the measure of average degree of dominance i.e. ?(?2s/? 2g).  Among the parents VN35I for plant height, Sanchita and VG26 for capsules per plant, VN23, VN35I and Vivek for capsule index, VG26 and Sanchita for seed and straw yield per plant, and VN35I and VG20 for morphine content were found good general combiners. Earliness being a desired trait, parent VG20 having significant negative GCA estimates coupled with per se performance can be considered as good general combiner for early flowering. Inclusion of good general combiners in a multiple crossing program or an inter-mating population involving all possible crosses among them subjected to bi-parental mating may be expected to offer maximum promise in breeding for economic traits.DOI: http://dx.doi.org/10.3329/bjpbg.v24i2.17000

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