scholarly journals Heterosis and genetic distance in intervarietal corn hybrids

Author(s):  
Diego Baretta ◽  
Maicon Nardino ◽  
Ivan Ricardo Carvalho ◽  
Alan Junior de Pelegrin ◽  
Mauricio Ferrari ◽  
...  

Abstract: The objective of this work was to evaluate the performance of intervarietal corn (Zea mays) hybrids with topcross crosses between landrace populations, and to confirm whether genetic dissimilarity between populations is correlated with the heterosis of the intervarietal hybrids in the field. Nine topcross hybrids were evaluated with their tester 'BRS Planalto', and the following landrace populations were used as parents: Argentino Branco, Dente de Ouro, Amarelão, Criolão, Caiano Rajado, Branco Oito Carreiras, Branco Roxo Índio, Cateto Branco, and Argentino Amarelo. The tester 'BRS Planalto' and the topcross hybrids Branco Oito Carreiras x 'BRS Planalto' and Criolão x 'BRS Planalto' showed higher per se potential for grain yield. The topcross hybrid Branco Oito Carreiras x 'BRS Planalto' showed a better performance for number of grains per row, grain weight, and ear diameter, whereas Criolão x 'BRS Planalto' displayed a better performance for the number of grains per row and ear length. Greater estimates of genetic distance did not necessarily result in greater heterosis values and were exclusively correlated with grain ear length. Therefore, it is not possible to predict the effects of high heterosis on grain yield, based on the genetic distance between the populations involved in the crosses.

2020 ◽  
Vol 5 (01) ◽  
pp. 45-49
Author(s):  
Ankit Kumar ◽  
Amit Tomar

The results revealed that parents namely, TSK-10, TSK-27, New Blue-II, Kurara and TSK-109 were found highly genetic diverse for days to 50% tasseling, days to 50% silking, days to 755 dry husk. The parents namely, TSK-109, Kurara, New Blue-II and TSK-10 were found highly genetic diverse for plant height (cm), cob height, number of cobs per plant and number of grains per cob. The parents namely, Kurara, TSK-109, TSK-10, New Blue-II and TSK-27 were found highly genetic diverse for shelling percentage, grain yield per plant, grain yield per cob and 100-grain weight.


2019 ◽  
Vol 37 ◽  
Author(s):  
L.B.P. BRAZ ◽  
G.B.P. BRAZ ◽  
S.O. PROCÓPIO ◽  
C.J.B. FERREIRA ◽  
A.G. SILVA ◽  
...  

ABSTRACT: The presence of volunteer corn plants in coexistence with soybean has been increasing since the introduction of glyphosate-resistant corn hybrids. This study aimed to evaluate the effect of interference of volunteer RR® corn plants at different densities on two RR® soybean cultivars. The experiment was conducted in Rio Verde, GO. The experimental design was a randomized block design in a factorial arrangement (2×5), with four replications. Factor A consisted of two soybean cultivars (BMX Potência RR® and M8210 IPRO®), while five densities of RR® corn plants per m2 (0, 4, 8, 12, and 16) were adopted for factor B. The following evaluations were carried out for soybean: plant height, SPAD index, percentage of interrow closure, shoot dry matter, first pod height, number of pods per plant, 100 grain weight, and grain yield of grains. Soybean plant height presented a linear and positive relationship with the increased density of corn plants. Shoot dry matter, 100 grain weight, number of pods per plant, and grain yield were negatively affected by the increased density of volunteer corn infestation. The soybean cultivar M8210 IPRO® was more susceptible to corn plant interference when compared to the cultivar BMX Potência RR®.


2019 ◽  
Vol 18 (1) ◽  
pp. 88-98
Author(s):  
GUSTAVO DE CARVALHO PERON ◽  
RENZO GARCIA VON PINHO ◽  
LUIZ ANTONIO YANES BERNARDO JÚNIOR ◽  
VANDER FILLIPE DE SOUZA ◽  
FRANCIELLY DE CÁSSIA PEREIRA ◽  
...  

RESUMO - Entender como o manejo de aplicação de fertilizantes interfere no sistema produtivo é primordial para amanutenção do máximo aproveitamento da produtividade dos híbridos. Desta forma, o objetivo com este trabalho foiverificar a influência da forma de adubação de semeadura, feita a lanço ou localizada, na produtividade de grãos de 33híbridos comerciais de milho, em quatro diferentes safras agrícolas. Foram conduzidos quatro experimentos no municípiode Serra do Salitre, em Minas Gerais (MG), nos meses de novembro de 2015 e de 2016, janeiro e fevereiro de 2017 efevereiro de 2017. O delineamento experimental utilizado foi o de blocos completos casualizados com três repetições,com os tratamentos dispostos em esquema fatorial de 33 x 2, sendo 33 híbridos de milho e dois sistemas de adubação desemeadura: a lanço e localizada. Na análise conjunta da produtividade de grãos, ocorreram interações significativas entrehíbridos e safras, e também entre formas de adubação e safras. Apesar da interação significativa, o sistema de adubaçãolocalizada foi superior em ambas as safras avaliadas, considerando nível de significância de 5% pelo teste de Tukey.Mesmo com as condições climáticas menos favoráveis na segunda safra, a adubação localizada mostrou-se mais eficiente.Palavras-chave: adubação localizada, adubação a lanço, segunda safra, Zea mays L.EFFECT OF SOWING FERTILIZATIONON GRAIN PRODUCTIVITY OF MAIZE HYBRIDSABSTRACT - Understanding how the management of fertilizer application affects the production system is essentialto maximize the productivity of the hybrids. The objective of this study was to verify the effect of broadcasting andbanding fertilization on grain yield of 33 commercial maize hybrids in four different crop seasons. Four experimentswere carried out in Serra do Salitre, state of Minas Gerais, Brazil, in November 2015, November 2016, January andFebruary 2017. The experimental design was a randomized complete block with three replications, with treatmentsarranged in a 33 x 2 factorial scheme, 33 corn hybrids and two sowing fertilization forms, broadcast and bandapplication. The joint analysis of grain yield showed significant interactions between hybrids and crop seasons, andalso between fertilization systems and crop seasons. The unfolding of the interaction between the fertilization formsand crop seasons showed that the yield of grains in the band fertilization was superior compared to the broadcastfertilization, regardless the crop season evaluated. Even with the less favourable climatic conditions in the secondharvest, the band fertilization showed to be more efficient when compared to the broadcast fertilization.Keywords: broadcast fertilizer, band fertilizer, second crop, Zea mays L.


1981 ◽  
Vol 61 (1) ◽  
pp. 29-36
Author(s):  
O. A. ADARA ◽  
L. W. KANNENBERG

Two cycles of S1 per se recurrent selection were conducted in four populations of corn (Zea mays L.). The primary selection criterion was a performance index: grain yield divided by percent moisture at harvest. The original (C0) source material and first cycle (C1) of selection for each population were evaluated in a favorable (1977) and an unfavorable (1978) growing season. Second cycle (C2) materials were also included in the 1978 comparisons. In 1977, C1 yielded significantly more grain than C0 in three of the four populations. In contrast, performance of C1 and C2 materials in 1978 was inferior to C0 in all populations but one. The advanced cycles of only one population showed improvement over C0 in both years. Comparisons of the 1977 data for days to silking, grain yield, and percent ear moisture at harvest suggest that rate of grain filling in C1 was higher than in C0 for all populations. The higher rates of grain filling in the advanced cycles may have caused a carbohydrate deficiency under stress (1978) so that the leaves no longer functioned normally and kernel filling was terminated prematurely. In general, the four populations showed inherent differences in their respective responses to selection, to environmental stress, and to inbreeding.


Author(s):  
Ahmed J. M. Habeeb ◽  
Intsar H. H. Al-Hilfy

Introduction: A Field experiment was conducted at the experimental farm, Dept. of Field Crop (Al-Jadriya), Coll. of Agric., Univ. of Baghdad to study the effects of brassinolide concentrations and spraying stages on yield and its components of maize (Baghdad 3 cultivar) during spring and autumn seasons in 2017. Materials and Methods: A randomized complete blocks design arranged in actorial experiment was used with three replicates. The first factor included three concentrations (0, 2 and 4 mg L-1) of brassinolide,and the second factor included spraying stages (4, 8, 12, 4 + 8, 4 + 12, and 8 + 12 leaves) using the same concentrations for each stage. Results and discussion: Results showed that the concentration 4 mg L-1 gave the highest grain yield (6.59 and 7.15 t ha-1) for its superiority in 500 grain weight (102.74 and 112.26 g) and number of ears per plant (1.43 and 1.44 ear) for both spring and autumn seasons, respectively. The spraying stage (4 + 8 leaves) recorded highest grain yield (6.33 and 6.77 t ha-1), and 500 grain weight (104.73 and 119.20 g) for both spring and autumn seasons, respectively. The effect of interaction for both factors was significant in most studied traits. Conclusion: Therefore, we recommend spraying Brassinolide in a concentration of 4 mg L-1 at the stage 4 + 8 leaves to increase grain yield of maize


1998 ◽  
Vol 12 (1) ◽  
pp. 41-46 ◽  
Author(s):  
Douglas J. Doohan ◽  
Jerry A. Ivany ◽  
Ronald P. White ◽  
William Thomas

The effect of DPX-79406 was evaluated on eight corn hybrids in 1993 and on 18 hybrids in 1994. Experiments were conducted each year at Charlottetown, Prince Edward Island, and Stewiacke, Nova Scotia. Corn tolerance was similiar between sites but varied from year to year with certain hybrids. Generally, tolerance was hybrid dependent. Most hybrids displayed chlorosis and stunting 7 days after treatment (DAT) but recovered quickly. Injury at 7 DAT ranged from 8 to 64%. Grain yield indicated that ‘Pickseed 2444,’ ‘Pioneer 3921,’ ‘Pioneer 3979,’ and ‘DK 302’ were tolerant to 25 g ai/ha of DPX-79406. Pioneer 3979 and Pickseed 2444 grain yields were reduced with DPX-79406 at 50 g/ha in 1 yr. ‘DK 291’ and ‘DK 235’ were severely injured both years and did not recover appreciably from early injury. Responses of ‘Pioneer 3984’ and ‘Pickseed 2477’ varied from year to year, and they were considered sensitive to DPX-79406. ‘Pioneer 3947,’ ‘Pioneer 3962,’ ‘Pickseed 2290,’ ‘Pickseed 2299,’ ‘DK 220,’ ‘G-4011,’ and ‘N0565’ were tested only 1 yr and were tolerant to both rates of DPX-79406.


Author(s):  
Rodrigo Véras da Costa ◽  
Dagma Dionísia da Silva ◽  
Luciano Viana Cota ◽  
Leonardo José Motta Campos ◽  
Rodrigo Estavam Munhoz de Almeida ◽  
...  

Abstract: The objective of this work was to evaluate the incidence of corn stunt disease and its effects on the grain yield of off-season corn (Zea mays) hybrids in different sowing seasons. The experiment was conducted in three sites in the state of Tocantins, in different sowing seasons, in a randomized complete block design, with 30 hybrids (treatments) and three replicates. Corn stunt disease incidence was assessed at 80 days after emergence, varying between hybrids and sowing seasons, with a marked effect of sowing season. The most resistant hybrids were: MG652 PW, Penta VIP, MG600 PW, NS90 PRO2, LG3040 VIP3, MG580 PW, and Defender VIP. The Fórmula VIP2 hybrid was the most susceptible to corn stunt disease. The incidence of the disease increased in the later sowing seasons, causing significant declines in grain yield. The most productive hybrids were: MG580 PW, SYN 5T78 VIP, 2B810 PRO, MG600 PW, Supremo VIP, 2B512 PW, NS92 PRO2, P30S31 VYH, MG652 PW, Penta VIP, SX5371 VIP3, and LG6036 PRO. Corn hybrids vary greatly in their resistance to corn stunt disease, and, the later the sowing season, the higher the disease incidence and the lower the grain yield.


2019 ◽  
Vol 1 (1) ◽  
Author(s):  
J. Ramirez ◽  
A. Soto ◽  
C. E. Durán ◽  
D. B. Luis

AbstractObjectives: To determine the effect of the time and the number of lower leaves defoliated, on the productivity of hybrid corn (Zea mays L.). Methodology: Randomized complete blocks design was used, with arrangement of split plot and four replications, using the hybrid cultivar DK 7088. The plots corresponded to the defoliation times: 0, 14 and 28 days after pollination (DAP) and the subplots, number of defoliated leaves (DL): zero, two,four and six. The leaves were defoliated just below the ear, from top to the bottom. The total number of treatments was 12. Scott-Knott statistical test with a level of 5 % was used for the comparison of means. The traits studied were grain weight per ear, ear weight and grain yield per hectare. Results: The interaction between defoliation time and number of lower defoliated leaves was significant (P < 0.05) for grain weight per ear, ear weight andgrain yield. The defoliation of two, four and six leaves during pollination reduced the grain weight per ear, weight per cob and grain yield, being significantly lower than the no defoliated plants. At 14 and 28 days after pollination, defoliation did not affect significantly (P > 0.05) grain yield, but grain weight per ear and ear weight decreased (P< 0.05). Conclusions: The defoliation of lower leaves made during the pollination, reduces the grain weight per ear, ear weight and grain yield, while defoliation 14 days after pollination did not affect significantly the grain yield per hectare.Keywords: Zea mays, defoliation, leaves, grain yield


2019 ◽  
Vol 40 (6Supl2) ◽  
pp. 2861
Author(s):  
André Prechlak Barbosa ◽  
Claudemir Zucareli ◽  
José Henrique Bizzarri Bazzo ◽  
Luis Abilio Ribeiro Alves ◽  
Renan Iastrenski

Growth regulators can be an important tool in corn crop management, especially in technology-intensive crops grown in densified spatial arrangements, under favorable environmental conditions, and using genotypes with greater vegetative development. The objective of this study was to evaluate the effect of growth regulators associated with sowing date on the growth characteristics, yield components, and grain yield of first-crop corn hybrids. The experiment was performed on a 2014/15 field crop, under a randomized complete block design with four replicates. Treatments were placed in a 2 × 2 × 3 factorial arrangement consisting of two sowing dates (first: 09/19/2014 and second: 11/23/2014), two corn hybrids (2B610PW and 2B810PW), and three conditions of growth regulators (control without application, 400 g a.i. ha-1 trinexapac-ethyl, and 200 g a.i. ha-1 clomazone, both applied when six fully expanded leaves were observed). The following characteristics were evaluated: plant height, ear insertion height, stem diameter, leaf area index, number of rows per ear, number of grains per row, number of grains per ear, ear length, ear diameter, prolificacy, thousand grain weight, and grain yield. Corn development and yield performance were altered by the interaction between sowing date, genotypes, and growth regulators. The second sowing date, which was not limited by water deficiency, resulted in better development and yield performance for the two hybrids. The 2B610 hybrid had a higher yield performance than did 2B810 in the second sowing date. Trinexapac-ethyl and clomazone contributed to higher corn grain yield from the two hybrids at the first sowing date and from the 2B810 hybrid at the second date. Trinexapac-ethyl reduced the size of the 2B810 hybrid at the second date. The growth and leaf area of the 2B810 hybrid were less affected by the restrictive conditions of the first sowing date; consequently, there was a higher grain weight performance that did not allow the differentiation of yield between genotypes for this sowing date.


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