scholarly journals Híbridos dobles de maíz de baja depresión endogámica en F2.

2016 ◽  
Vol 9 (1) ◽  
pp. 38 ◽  
Author(s):  
Humberto De León ◽  
Arcenio Jaramillo ◽  
Gaspar Martínez ◽  
Sergio Rodríguez
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Inbreeding Depression ◽  
High Yield ◽  
Stem Height ◽  
Ear Height ◽  
Root Lodging ◽  
Yield Decrease

The first and second generations (F1 and F2) of 33 double hybrids of com were studied in order to evaluate grain yield decrease caused by generational advance, and to detect hybrids with a low inbreeding depression. Effects of in breeding depression were also evaluated according to flowering days (FD), plant height (PH), ear height (EH), root lodging (RL), and stem height (SH), bad coverage (BC), and roUen ears (RE). Doub1e hybrids with a high yield were obtained in F1, and without in breeding in F2 at arate of six to nine percent, depending on the evaluation environment, indicating insignificant in breeding effects.

scholarly journals Combining abilities and inbreeding depression in commercial maize hybrids

2015 ◽  
Vol 36 (6Supl2) ◽  
pp. 4133
Author(s):  
Henrique José Camargo Senhorinho ◽  
Ronald José Barth Pinto ◽  
Carlos Alberto Scapim ◽  
Klayton Flávio Milani ◽  
Thiago Hideyo Nihei
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Inbreeding Depression ◽  
Combining Ability ◽  
Recurrent Selection ◽  
Inbred Lines ◽  
Square Lattice ◽  
Reciprocal Recurrent Selection ◽  
Maize Hybrids ◽  
Ear Height

<p>The objective of this study was to evaluate the combining ability and inbreeding depression of commercial maize hybrids for agricultural traits. Twenty-two commercial maize hybrids, 96 F1 crosses from a partial diallel scheme, 22 S1 populations and 4 controls were evaluated in a 12x12 simples square lattice experimental setup, totaling 144 treatments, in the municipality of Sabáudia (PR), Brazil, for harvests from 2011/2012 and 2012/2013. Three traits were evaluated: grain yield, plant height and ear height. The Griffing method (1956) was applied for the evaluation of the general combining ability (GCA) and specific combining ability (SCA). The 30B39, 30K64 and 30B30 hybrids showed increased yield, 30F53 and P1630 showed reduced plant height and AG9040 and AG7010 showed reduced ear height. These hybrids can be recommended for the extraction of inbred lines and formation of composites followed by intrapopulation selection. The combinations 30B39 x AG8088, 30B39 x AG9045 and P1630 x AG8021 showed desirable SCA effects for grain yield, plant height and ear height and are recommended for use in reciprocal recurrent selection programs. High magnitudes of inbreeding depression were verified for yield and lower values for inbreeding depression for plant and ear heights. Thus, strategies are recommended for interpopulation breeding accompanied by inbred lines extraction.</p>

scholarly journals Combining abilities and inbreeding depression in commercial maize hybrids

2015 ◽  
Vol 36 (6Supl2) ◽  
pp. 4133
Author(s):  
Henrique José Camargo Senhorinho ◽  
Ronald José Barth Pinto ◽  
Carlos Alberto Scapim ◽  
Klayton Flávio Milani ◽  
Thiago Hideyo Nihei
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Inbreeding Depression ◽  
Combining Ability ◽  
Recurrent Selection ◽  
Inbred Lines ◽  
Square Lattice ◽  
Reciprocal Recurrent Selection ◽  
Maize Hybrids ◽  
Ear Height

The objective of this study was to evaluate the combining ability and inbreeding depression of commercial maize hybrids for agricultural traits. Twenty-two commercial maize hybrids, 96 F1 crosses from a partial diallel scheme, 22 S1 populations and 4 controls were evaluated in a 12x12 simples square lattice experimental setup, totaling 144 treatments, in the municipality of Sabáudia (PR), Brazil, for harvests from 2011/2012 and 2012/2013. Three traits were evaluated: grain yield, plant height and ear height. The Griffing method (1956) was applied for the evaluation of the general combining ability (GCA) and specific combining ability (SCA). The 30B39, 30K64 and 30B30 hybrids showed increased yield, 30F53 and P1630 showed reduced plant height and AG9040 and AG7010 showed reduced ear height. These hybrids can be recommended for the extraction of inbred lines and formation of composites followed by intrapopulation selection. The combinations 30B39 x AG8088, 30B39 x AG9045 and P1630 x AG8021 showed desirable SCA effects for grain yield, plant height and ear height and are recommended for use in reciprocal recurrent selection programs. High magnitudes of inbreeding depression were verified for yield and lower values for inbreeding depression for plant and ear heights. Thus, strategies are recommended for interpopulation breeding accompanied by inbred lines extraction.

Genetic variation and association study for grain yield in germplasm accessions of maize (zea mays L.)

2017 ◽  
Author(s):  
Niharika Shukla
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Male Flower ◽  
Female Flower ◽  
Kernel Weight ◽  
High Yield ◽  
Phenotypic Correlation ◽  
Flower Initiation ◽  
Germplasm Collections ◽  
Ear Height

The present investigation aimed to find out the association among yield and its components and to sort out the traits that are directly or indirectly contributing towards yield in landraces of maize genotypes. The eighty eight (88) maize germplasm collections were used in present study during Kharif -2012 and Kharif -2013 in RCBD design. Pooled data and standard statistics were employed (means, ranges, GM±SE, standard error and coefficient of variation etc.) for analysis of the seventeen quantitative traits to have a reflection of the level of genetic variability. A considerable amount of variability was found among germplasms for various important traits viz. plant height, ear weight, ear length, 1000 kernel weight similarly grain yield per plant etc. grain yield exhibited positive and highly significant correlation with ear height, days to female flower initiation, days to 50% male flower initiation, days to 50% female flower initiation, days to maturity, 1000 grain weight, ear weight at genotypic and phenotypic level. Maximum phenotypic correlation coefficient was recorded by cob diameter (0.955) followed by days to female flower initiation (0.758), plant height (0.718*) and days to male flower initiation (0.679).Path analysis indicated that the character ear height (0.410) recorded highest of the direct effect followed by biological yield per plant (0.408), harvest index (0.328), days to female flower initiation (0.32), prop root (0.149) and 1000 kernel weight (0.136), so such traits may be rewarding and they should be given importance while practicing selection, aimed at improving grain yield per plant in maize. The genotypes JLM 22 was to be found best for high yield by considering all yield contributing traits followed by JLM 51, HKI 1344, CML 429, CML 470, JLM 30 JLM 2 and these can be utilized in further breeding programmes for producing single cross hybrids in Maize.

scholarly journals Green ear yield and grain yield of maize cultivars in competition with weeds

2010 ◽  
Vol 28 (1) ◽  
pp. 77-85 ◽  
Author(s):  
P.S.L. Silva ◽  
K.M.B. Silva ◽  
P.I.B. Silva ◽  
V.R. Oliveira ◽  
J.L.B. Ferreira
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Block Design ◽  
Corn Yield ◽  
Modern Agriculture ◽  
Maize Cultivars ◽  
Randomized Complete Block Design ◽  
Ear Height ◽  
Herbicide Use ◽  
Ground Part

The reduction in herbicide use is one of the greatest interests for modern agriculture and several alternatives are being investigated with this objective, including the adoption of cultivars that suppress weeds. The objective of this study was to verify if maize cultivars develop differently, in competition with weeds, to produce green ears and grain. Randomized complete block design was used, with split-plots and five replications. Cultivars DKB 390, DKB 466, DKB 350, AG 7000, AG 7575 and Master, were evaluated in the plots, without weeding and two weedings (at 22 and 41 days after sowing) in sub plots. Twenty-one species were identified in the experimental area, the most frequent being Gramineae (Poaceae), Euphorbiaceae, Leguminosae (Fabaceae) and Convolvulaceae species. There was no difference in the dry biomass above-ground part of the weeds in the plots of the evaluated cultivars. The cultivars behaved similarly in treatments with or without hoeing, except for plant height and ear height evaluations. Without hoeing, plant height increased in cultivar DKB 390, while plant height and ear height decreased in cultivar AG 7575. In the other cultivars, these traits did not change under weed control. The presence of weeds decreased the values of all traits employed to assess green corn yield, with the exception of the total number of green ears and grain yield.

Combining ability and heterosis studyin maize inbreds throughout diallel mating design

2018 ◽  
Vol 43 (4) ◽  
pp. 599-609
Author(s):  
ANMS Karim ◽  
S Ahmed ◽  
AH Akhi ◽  
MZA Talukder ◽  
A Karim
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Combining Ability ◽  
Gene Action ◽  
General Combining Ability ◽  
Specific Combining Ability ◽  
Gene Effects ◽  
Additive Type ◽  
Additive Gene ◽  
Ear Height

Combining ability effects were estimated for grain yield and some other important agronomic traits of maize in a 7×7 diallel analysis excluding reciprocals. The variances for general combining ability (GCA) were found significant for yield, days to pollen shedding, days to silking and ear height while it was found non-significant for plant height and number of kernels/ear. Non-significant general combining ability (GCA) variance for plant height and number of kernels/ear indicates that these two traits were predominantly controlled by non- additive type of gene action. Specific combining ability (SCA) was significant for all the characters except yield and days to silking. Non-significant specific combining ability (SCA) variance for yield and days to silking suggests that these two traits were predominantly controlled by additive type of gene action. Both GCA and SCA variances were found significant only in days to pollen shedding and ear height indicated the presence of additive as well as non additive gene effects for controlling the traits. However, relative magnitude of these variances indicated that additive gene effects were more prominent for all the characters studied except days to silking. Parent BIL95 was the best general combiner for both high yield and number of kernels/ear and parent BML4 for dwarf plant type. Two crosses (BML4× BML36 and BIL114× BIL31) exhibited significant and positive SCA effects for grain yield involved low × average and average × average general combining parents. The range of heterosis expressed by different crosses for grain yield and days to silking was from -65.83 to 21.26 percent and -17.85 to 8.22 percent, respectively.. The better performing three crosses (BIL114×BIL31, BIL138×BIL95 and BIL31×BIL95) can be utilized for developing high yielding hybrid varieties as well as for exploiting hybrid vigour.Bangladesh J. Agril. Res. 43(4): 599-609, December 2018

THREE GENERATIONS OF INBREEDING AND S2 FACTORIAL TEST CROSSES IN RED RASPBERRY CULTIVARS

1974 ◽  
Vol 16 (2) ◽  
pp. 419-432 ◽  
Author(s):  
S. O. Fejer ◽  
L. P. S. Spangelo
Keyword(s):  
Plant Height ◽  
Inbreeding Depression ◽  
Breeding Program ◽  
High Yield ◽  
Realized Heritability ◽  
Red Raspberry ◽  
Diallel Crosses ◽  
Berry Quality ◽  
Selection For ◽  
Early Vigor

In selfed (S1 to 33) progenies of red raspberry cultivars, inbreeding depression progressively reduced plant height in spite of selection for vigor. Parent-offspring correlations indicated high realized heritability of this character. High yield was correlated in this material with many laterals, early flowering, tall new canes, and good berry quality but not with winter resistance. Heritability in the broad sense was high for early vigor, plant height and winter resistance, lower for berry weight and flowering day, and very low for yield and its morphological components, but selection for vigor may have influenced these estimates.In a second experiment five S2 progenies and their parent cultivars Muskoka, Trent and Tweed were crossed with three tester plants, Ottawa Latham, Viking and 45-01-56. Some of the S2 × tester progenies were superior in a number of yield characters to those produced when their parent cultivar was crossed to the same testers. The results were similar to those with strawberry (Spangelo et al., 1971), suggesting that inbreeding may sometimes be a useful step in a raspberry breeding program for higher yield. However, inbred × inbred crosses were generally poor. General and specific combining abilities were mostly similar in three different samples of factorial ("¼ diallel") crosses, but there were many exceptions possibly due to genotype-environment interactions. Most of the correlations were significant in this trial and the highest ones were in agreement with the correlations in the inbreeding trial.

Identification of QTLs for plant height, ear height and grain yield in maize (Zea mays L.) in response to nitrogen and phosphorus supply

2012 ◽  
Vol 131 (4) ◽  
pp. 502-510 ◽  
Author(s):  
Hongguang Cai ◽  
Qun Chu ◽  
Riliang Gu ◽  
Lixing Yuan ◽  
Jianchao Liu ◽  
...  
Keyword(s):  
Zea Mays ◽  
Grain Yield ◽  
Plant Height ◽  
Zea Mays L ◽  
Nitrogen And Phosphorus ◽  
Ear Height

scholarly journals Agronomic Performance and Genetic Divergence in Corn (Zea mays) in the Cerrado-Amazon Ecotone

2019 ◽  
pp. 1-7
Author(s):  
Rafael Marcelino Da Silva ◽  
Weder Ferreira dos Santos ◽  
Matheus Rodrigues de Andrade ◽  
Zildiney Dantas Da Silva ◽  
Layanni Ferreira Sodré Santos ◽  
...  
Keyword(s):  
Zea Mays ◽  
Experimental Design ◽  
Grain Yield ◽  
Plant Height ◽  
Genetic Divergence ◽  
Optimization Method ◽  
Multivariate Model ◽  
Agronomic Performance ◽  
Ear Height ◽  
Generalized Distance

The objective of this work is to study the agronomic performance and genetic divergence in corn in the Cerrado-Amazon ecotone. The trials were conducted in the 2017/18 harvest at a property in the state of Pará. The experimental design was a randomized block with nine treatments and three replications, where the treatments are represented by nine cultivars of corn. The characteristics to evaluate agronomic performance and genetic divergence were: ear height (cm), plant height (cm), ear length (cm), ear diameter (mm), number of rows, number of grains per row and grain yield (kg ha−1). The cultivars were separated into a multivariate model in five groups using the Tocher optimization method. The cultivar AG 1051 showed the best agronomic performance. The results of genetic divergence were according to the generalized distance of Mahalanobis (D2), with the commences AG 8088 x CATIVERDE and AG 1051 x AL BANDEIRANTE, the most promising for future crosses.

scholarly journals Predicting the range of inbreeding depression of inbred lines in cross-pollinated populations

1997 ◽  
Vol 20 (1) ◽  
pp. 35-39 ◽  
Author(s):  
C.L. Souza Jr. ◽  
J.S.C. Fernandes
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Inbreeding Depression ◽  
Genetic Variance ◽  
Inbred Lines ◽  
Gene Frequencies ◽  
Mating Design ◽  
Inbreeding Coefficients ◽  
Maize Population ◽  
Two Generations

The objectives of this paper were to derive the genetic variance of inbreeding depression (<img SRC="Image482.gif" WIDTH="48" HEIGHT="33"> ) and to predict the range of inbreeding depression (RID) in cross-pollinated populations. The variance of inbreeding depression is a function of the genetic variances related to dominance effects (<img SRC="Image483.gif" WIDTH="31" HEIGHT="33">, D2, and <img SRC="Image484.gif" WIDTH="21" HEIGHT="25">), and of the inbreeding coefficients of the two generations in which inbreeding depression is measured (Ft and Fg). The results showed that the higher the level of dominance of a trait, the higher the variance of inbreeding depression. The magnitudes of <img SRC="Image485.gif" WIDTH="48" HEIGHT="33">were expected to be lower in improved (mean gene frequencies = <img SRC="Image486.gif" WIDTH="16" HEIGHT="25">> 0.6) and in unimproved (<img SRC="Image487.gif" WIDTH="16" HEIGHT="25"> < 0.4) populations, than in composite populations (<img SRC="Image487.gif" WIDTH="16" HEIGHT="25"> <FONT FACE="Symbol">»</font> 0.5). Data from a maize population used to illustrate the study showed that the range of inbreeding depression in the S<FONT FACE="Symbol">¥</font> generation of selfing was from 48.7% to 85.3% for grain yield, and from 13.9% to 24.5% for plant height. A mating design outlined to estimate the genetic variance of inbreeding depression, the range of inbreeding depression, and of the range of inbred lines is presented.

scholarly journals Genetic Evaluation and Correlation Analysis Among Various Quantitative Traits in Maize Single-Cross Hybrids Under Diverse Environments

2021 ◽  
Vol 13 (5) ◽  
pp. 104
Author(s):  
Fortunate Makore ◽  
Cosmos Magorokosho ◽  
Shorai Dari ◽  
Edmore Gasura ◽  
Upenyu Mazarura ◽  
...  
Keyword(s):  
Grain Yield ◽  
Plant Height ◽  
Coefficient Of Variation ◽  
Strong Positive Correlation ◽  
Genetic Advance ◽  
Positive Correlation ◽  
Grain Moisture ◽  
High Heritability ◽  
Ear Height ◽  
Positive Direct

Genetic variation abundance, high genetic advance coupled with high heritability estimates presents the most suitable condition for selection. Ninety-five hybrids generated from elite and new inbred lines crossed using half diallel mating design were evaluated under diverse environments. The objectives were to estimate genetic variances, heritability of traits and genetic advance and to determine correlations of grain yield and its component characters in maize hybrids. Analysis of variance revealed significant differences among genotypes for all traits studied except for ear rots. Estimates of phenotypic coefficient of variation were slightly higher than genotypic coefficient of variation for all traits suggesting low influence of environment in the expression of these traits. High heritability and genetic estimates were recorded for grain yield (79%; 30.27%), plant height (85%; 102.42%) and ear height (86%; 117.15%) whilst high heritability and low genetic advance were observed for anthesis date (87%; 5.8%), texture (75%; 8%) and ear position (71%; 0.23%). Correlation between environments using grain yield data revealed existence of a very strong positive correlation between CIMMYT2 and RARS2 suggesting that the sites have the same discriminating effect. Correlation among traits revealed that grain yield had significant (P &lt; 0.05) positive correlation with plant height and ear height. Similarly, plant height had significant and positive correlation with ear height while ear position was positively correlated to ear height. Path analysis showed that plant height, ears per plant and ear position had positive direct effects on grain, while anthesis date, ear height, ear position, grain moisture content at harvest and texture indirectly influenced grain yield. These characters&rsquo; contribution to grain yield is important and the strong association with grain yield implied that these can be used as secondary traits to indirectly select for grain yield performance in this set of germplasm across all the environments.

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