GENETIC RELATIONSHIPS BETWEEN GRAIN YIELD AND YIELD COMPONENTS IN A SYNTHETIC MAIZE POPULATION AND THEIR IMPLICATIONS IN SELECTION

2001 ◽  
Vol 49 (4) ◽  
pp. 337-342 ◽  
Author(s):  
N. VASIC ◽  
M. IVANOVIC ◽  
L. A. PETERNELLI ◽  
D. JOCKOVIC ◽  
M. STOJAKOVIC ◽  
...  
Keyword(s):  
Grain Yield ◽  
Genetic Correlation ◽  
Yield Components ◽  
Genetic Relationships ◽  
Maize Population ◽  
Selection Indices ◽  
Ear Height ◽  
Selection For ◽  
Efficiency Of Selection ◽  
Simple Selection

The synthetic maize population 316PO2 was subjected to genetic correlation analyses between grain yield, yield components and morphological traits. The purpose was to enable estimates to be made of the advantage of using selection indices compared with selection based on grain yield only, and if that advantage was present, to choose enough simple selection indices for practical use. Selection indices were constructed out of four traits highly significantly correlated with grain yield, in addition to yield itself. Grain yield exhibited a highly significant additive genetic correlation with ear diameter (ra=0.588**), kernels row-1 (ra=0.643**), ears plant-1 (ra=0.871**) and ear height (ra=0.427**). The most efficient index was Index No. 14 (R.E.I12345= 108.83%), which included all four traits and grain yield. Index No. 3, one of the simplest forms of index, including only ears plant-1 and grain yield, showed slightly less relative efficiency (R.E.I35=107.24%) than Index No. 14. Using this simple form of index with two characters (Index No. 3) could improve the efficiency of selection for grain yield. The estimated advantage from its use is 179.6 kg/selection cycle for grain yield over selection based only on grain yield.

scholarly journals Genetic correlation between traits in the ESALQ-PB1 maize population divergently selected for tassel size and ear height

2001 ◽  
Vol 58 (1) ◽  
pp. 119-123 ◽  
Author(s):  
Austeclínio Lopes Farias Neto ◽  
José Branco de Miranda Filho
Keyword(s):  
Genetic Correlation ◽  
Correlation Coefficients ◽  
Divergent Selection ◽  
Phenotypic Correlation ◽  
Base Population ◽  
Branch Number ◽  
Maize Population ◽  
Tassel Branch Number ◽  
Ear Height ◽  
Selection For

Full-sib and selfed (S1) progenies were obtained from sub-populations of ESALQ-PB1, divergently selected for tassel size (T+ and T-) and ear height (E+ and E-), and used for estimating genetic and phenotypic correlation coefficients between traits. The analyzed traits were: EW- total ear weight (g/plant), PH- plant height (cm), EH- ear height (cm), TB- tassel branch number and TL- tassel length. The highest genetic (rG) and phenotypic (rF) correlation was observed for the combination PH x EH, as expected, with average of 0.800 and 0.778, respectively over sub-populations and locations. It is apparent that divergent selection for tassel size did not affect greatly the correlation between PH and EH in the full sib progenies, but in the inbred progenies the correlation was smaller in the sub-population selected for larger tassels. Genetic correlation between PH and EH with tassel traits was always positive but ranged from 0.020 to 0.668 in Piracicaba and from 0.06 to 0.309 in Rio Verde. Genetic correlation between PH and EH with yield (EW) also was positive in the range of 0.087 to 0.503. EH showed higher correlation with EW in relation to PH x EW and differences were larger in the sub-populations divergently selected for ear height. Correlation between tassel traits with other traits was positive in most of instances and a lack of consistency was observed among sub-populations. Generally the coefficients of genetic and phenotypic correlation differed substantially from the estimates in the base population ESALQ-PB1 before divergent selection for tassel size and ear placement. Divergent selection affected the correlation between traits under unpredicted and varying magnitudes.

Changes in genetic variances and heritabilities in an early white maize population following S1 selection for grain yield, Striga resistance and drought tolerance

2016 ◽  
Vol 155 (4) ◽  
pp. 629-642 ◽  
Author(s):  
B. BADU-APRAKU ◽  
M. OYEKUNLE ◽  
A. O. TALABI ◽  
B. ANNOR ◽  
I. C. AKAOGU
Keyword(s):  
Drought Tolerance ◽  
Grain Yield ◽  
Recurrent Selection ◽  
Central Africa ◽  
Maize Production ◽  
Genetic Variances ◽  
Maize Population ◽  
Ear Height ◽  
Selection For ◽  
Advanced Cycles

SUMMARYDrought is a major constraint to maize production in West and Central Africa (WCA). Assessment of genetic gain from S1 recurrent selection under drought is crucial for the development of drought tolerance breeding strategies. In an early white population, 60 S1 families each derived from the base population and three cycles of selection were evaluated under drought and well-watered conditions at two locations in Nigeria for 2 years to determine genetic variability, gains from selection and predict response to selection for grain yield and other traits. Genetic variances generally decreased for yield and other traits in advanced cycles under drought and well-watered conditions except yield and ear height under well-watered conditions. Similarly, heritabilities for yield and other traits decreased in advanced cycles under drought but increased in advanced cycles under well-watered conditions. Realized gain for yield was 0·291 t/ha, corresponding to 30·5% per cycle under drought and 0·352 kg/ha with a corresponding gain of 16·7% per cycle under well-watered conditions. Predicted gain based on C3 was 0·282 and 0·583 t/ha under drought and well-watered conditions. Low genetic variances, heritabilities and predicted gain for yield and other traits suggested a need to introgress drought tolerance genes into the population.

ESTIMATES OF GENETIC CORRELATIONS AMONG CERTAIN CARCASS AND PERFORMANCE TRAITS IN SWINE

1968 ◽  
Vol 48 (1) ◽  
pp. 1-6 ◽  
Author(s):  
G. L. Roy ◽  
W. J. Boylan ◽  
M. E. Seale
Keyword(s):  
Birth Weight ◽  
Genetic Correlation ◽  
Genetic Relationships ◽  
Carcass Traits ◽  
Genetic Correlations ◽  
Development Project ◽  
Carcass Trait ◽  
Selection For ◽  
And Performance ◽  
Daily Gain

Data from a swine breed development project provided estimates of the genetic correlation among six performance and carcass traits. The data from the new breed, called Managra, were obtained over a 7-year period. Most genetic relationships examined were such that selection for improvement of one trait would yield a favorable improvement in another. Both carcass backfat and live backfat probe were found to be negatively correlated with area of loin eye and length of carcass. A positive genetic correlation was found between post-weaning daily gain and loin eye area. A high positive genetic correlation was found between birth weight and loin eye area. An unfavorable association involved a positive genetic correlation between birth weight and backfat.Correction factors for effect of carcass weight on the magnitude of carcass trait measurements and differences in means between sexes were obtained.Heritability of the traits was estimated by paternal half-sib correlation. The estimates for carcass traits were moderately high and agree well with most other estimates reported in the literature.

scholarly journals Effects of Selection for Yield Components on Grain Yield in Pearl Millet (Pennisetum typhoideumRich.)

1998 ◽  
Vol 1 (1) ◽  
pp. 52-55 ◽  
Author(s):  
Totok Agung Dwi Haryanto ◽  
Tae-Kwon Shon ◽  
Tomohiko Yoshida
Keyword(s):  
Grain Yield ◽  
Pearl Millet ◽  
Yield Components ◽  
Selection For

Effect of sampling errors on efficiency of selection indices. 2. Use of information on associated traits for improvement of a single important trait

1976 ◽  
Vol 23 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Jill Sales ◽  
W. G. Hill
Keyword(s):  
Selection Index ◽  
Heritability Estimate ◽  
Parameter Estimates ◽  
Response To Selection ◽  
Sampling Errors ◽  
Estimation Of Parameters ◽  
Selection Indices ◽  
Important Trait ◽  
Selection For ◽  
Efficiency Of Selection

SUMMARYAn analysis is undertaken of the effect of errors in estimates of parameters on the response to selection for an economically important trait (trait 1) when one or more additional traits are added in a selection index. The detailed analysis is confined to one additional trait (trait 2) which contributes useful information unless the genetic and phenotypic regressions of trait 1 on trait 2 are equal.If there are errors in parameter estimates the extra response obtained by including trait 2 will usually be over-predicted. When trait 2 actually contributes no useful information the predicted benefit equals the real loss in efficiency from its inclusion.The loss in efficiency from poor estimation of parameters, whether or not the second trait makes a contribution, is roughly one-quarter of the squared coefficient of variation of a heritability estimate of trait 1 in the same experiment.

scholarly journals Selección en cruzas interraciales tropicales de maíz de México para adaptación a valles altos

2016 ◽  
Vol 3 ◽  
pp. 23
Author(s):  
Alejandro A. Navas ◽  
Tarcicio Cervantes
Keyword(s):  
Grain Yield ◽  
Local Control ◽  
Yield Components ◽  
Selection Response ◽  
Average Response ◽  
Altitude Range ◽  
Selection Cycle ◽  
Local Populations ◽  
Gene Contribution ◽  
Selection For

The response of the selection, and its adaptation at high plateaus, of five generations of tropical corn race crosses from Mexico, with a 0- 700 masl altitude range, was evaluated. An assay was planted at Montecillo, Mexico (locale with high plateaus) using four generations of 22 tropical interracial crosses, nine race progenitors and four local populations as controls. Besides of the grain yield per stalk, 15 characters were studied, some as yield components and others as of agronomic interest for its adaptation. The selection for high platea u adaptation with tropical corn inter-racial crosses was efective to increase grain yield per stalk, achiering an average response of 18% per selection cycle, in five cycles. Although with smaller increments, the number of ears per stalk, lenght, diameter and grain percentage of the ear, volume and weight of 100 seeds were modified. Ear and plant height showed undesirable agronomic responses, while days to tasselling, blooming coincidence and plant health improved with the selection. Six crosses in F8 were identified as matching the yield and other characters to the best local control Huamantla (conical race). According to the progenitors used in these crosses, it is deduced that the Tuxpeño race was the largest gene contributor for yield and Vandeño for adaptation genes, while Tepecintle showed a very poor gene contribution to the selection response.

scholarly journals Introgression of Temperate Material to Improve Grain Yield in a Tropical Maize Population

2021 ◽  
Vol 9 (4) ◽  
pp. 39-42
Author(s):  
Justin Abadassi ◽  
Keyword(s):  
Grain Yield ◽  
Harvest Index ◽  
Recurrent Selection ◽  
Block Design ◽  
Tropical Maize ◽  
Maize Population ◽  
Randomized Complete Block Design ◽  
Ear Height

The effect of introgression of the temperate maize population BUGARD on the grain yield of a low-yielding tropical maize population well appreciated for the quality of its grains, NCP80, was studied. NCP80 was crossed with BUGARD to obtain the F1. The BC1 obtained by backcrossing the F1 to NCP80 was random mated thrice. The tropical parent NCP80 and the BC1 (NBN) were evaluated in two tropical locations using a randomized complete block design with three replications. Introgression of the temperate population BUGARD into the tropical population NCP80 significantly increased grain yield. The resulting population, NBN, appeared, moreover, significantly earlier than NCP80 and not significantly different from it for resistance to rust, tropical blight and maize streak, ear height, husk cover and harvest index. NBN may, further, be improved for resistance to maize streak and grain yield by recurrent selection.

scholarly journals Agronomic performance and genotypic diversity for morphological traits among early maize genotypes

2018 ◽  
Vol 2 (2) ◽  
Author(s):  
Bhim Nath Adhikari ◽  
Jiban Shrestha ◽  
Bishal Dhakal ◽  
Bishnu Prasad Joshi ◽  
Naba Raj Bhatta
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Yield Components ◽  
Zea Mays L ◽  
Genotypic Diversity ◽  
Agronomic Performance ◽  
Breeding Programs ◽  
Maize Germplasm ◽  
Maize Genotypes ◽  
Ear Height

Detailed information on the genetic diversity between maize germplasm (Zea mays L.) is useful for their systematic and efficient use in breeding programs. Fourteen early maize genotypes were studied to assess their performance and genotypic diversity at Doti, Nepal in 2015. Days to tasseling, days to silking, plant height, ear height, ear length, ear diameter and grain yield were significant among genotypes. Genotype SO3TEY-PO-BM, COMPOL-NIOBP and ACROSS-99402 were found higher yielder with earlier maturity. Days to tasseling (0.85), days to silking (0.82), plant height (0.79), ear length (0.71) and ear diameter (0.66) were found highly heritable traits. Grain yield (0.39) and ear height (0.47) medium and remaining traits showed low heritability. High PCV was observed for grain yield (35.10%), number of plants/plot (34.46%), tesseling silking interval (26.85%), harvested ears/plot (24.45%) and husk cover rating (22.85%) where other traits showed medium to low PCV. Grain yield showed high GCV (21.96%), ear height and husk cover had medium and remaining traits showed low GCV (<10%). Plant height (r₌0.498), harvested plants/plot (r₌0.412), harvested ear/plot (r₌0.762), ear length (r₌0.472) and ear diameter (r₌0.470) showed significant positive correlation with grain yield. The yield can be improved if selection applied in favor of those yield components.

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