R-nj ALEURONE COLOR SELECTION AND NITROGEN RESPONSE IN OPAQUE-2 MAIZE

1989 ◽  
Vol 69 (3) ◽  
pp. 741-747
Author(s):  
H. Z. CROSS ◽  
H. DOSSO
Keyword(s):  
Field Experiments ◽  
Agronomic Traits ◽  
Seedling Emergence ◽  
Kernel Weight ◽  
Low Fertility ◽  
Correlated Response ◽  
Mass Selection ◽  
Nitrogen Response ◽  
Color Selection ◽  
Selection For

Field experiments were conducted to determine if mass selection for degree of aleurone anthocyanin pigmentation controlled by R-nj could improve agronomic deficiencies associated with the o2 (opaque) phenotype of a maize (Zea mays L.) synthetic (NDSE). Divergent mass selection was used to develop high color (HC), low color (LC), and randomly sampled (RC) check substrains which were tested in 1982 at two low-fertility, pollen isolated sites (a clay loam, Vertic Haplaquoll with 7.2 pH and a silt loam, Aerie Calciaquoll with a 7.6 pH at Fargo and Casselton, N.D., respectively). Grain yield and agronomic traits were estimated for each of four N application rates at each site. N fertilizer increased grain yields and kernel weights. High color strains yielded highest at 136 kg ha−1 of N, outproducing RC strains. At 204 kg ha−1 of N, yield of HC strains declined and LC strains out-yielded HC strains. Low color selection significantly increased test weight, kernel weight, cob diameter, seedling emergence, and shelling ratio compared to RC strains in NDSE while HC selection increased kernel weight, cob diameter, and reduced ear moisture and protein contents compared to RC selection. Selection for LC improved several traits which were deficient in opaque-2 maize, and use of the R-nj gene may be useful in improving opaque-2 maize.Key words: Aleurone, anthocyanin, correlated response, ear moisture, mass selection, maize.

scholarly journals Grain filling of R-nj color-selected maize strains divergently selected for kernel weight

1994 ◽  
Vol 74 (3) ◽  
pp. 455-460
Author(s):  
H. Z. Cross ◽  
M. R. Mostafavi
Keyword(s):  
Field Experiments ◽  
Grain Filling ◽  
Kernel Weight ◽  
Lag Phase ◽  
Mass Selection ◽  
Dry Matter Accumulation ◽  
Phase Duration ◽  
Color Selection ◽  
Selection For ◽  
Grain Filling Period

Grain-fill characteristics in maize (Zea mays L.) affect yield by changing kernel weight. The objective of this study was to learn how divergent tandem selection for R-nj color expression and kernel weight affected rate of dry matter accumulation (RDMA), effective grain-filling period (EFPD), and lag phase duration (LAGP). We studied development of apical, mid-ear, and basal kernels in two genetic backgrounds. We derived 12 maize strains by tandem selection within each of two early-maturing synthetics. Mass selection of synthetics NDSF and NDSD for four cycles for high (HC), random (RC), and low (LC) R-nj color expression produced six substrains. Then, four cycles of divergent mass selection for kernel weight within each color-derived substrain produced 12 substrains for study. Using the 12 strains, we conducted field experiments using a completely random experimental design within each of 2 yr at Fargo, ND. Sequential kernel samples of individual ears within each strain provided data to estimate RDMA, EFPD, LAGP, and five-kernel weight (KWT). We sampled at 3- to 4-d intervals during the linear phase of grain-filling and at maturity. Selection for HC increased RDMA but tended to decrease EFPD compared to LC strains in both NDSF and NDSD. Selecting heavier kernels increased KWT of basal and mid-ear kernels by increasing RDMA. Direct and correlated responses to R-nj color selection were evident after four subsequent cycles of divergent tandem selection for kernel weight. Therefore, R-nj expression was not a temporary maternal effect. Kernel weight selection responses differed among the color strains and synthetics. Kernel weight seemed mainly determined by RDMA that was affected by selection for R-nj color expression and for kernel mass. Key words:Zea mays L., aleurone color, mass selection, correlation, yield components

Ear moisture during kernel development as influenced by field and laboratory selection

1995 ◽  
Vol 75 (3) ◽  
pp. 557-563 ◽  
Author(s):  
H. Z. Cross
Keyword(s):  
Moisture Content ◽  
Field Study ◽  
Agronomic Traits ◽  
Grain Filling ◽  
Kernel Weight ◽  
Test Weight ◽  
Mass Selection ◽  
Dry Matter Accumulation ◽  
Drying Characteristics ◽  
Laboratory Selection

Grain quality, timeliness of harvest, and profitability can be increased by improving field drying characteristics of maize (Zea mays L.) hybrids. To better understand hows genes control ear drying, I compared maize strains developed by divergently selecting three cycles for (1) high HM or low LM moisture content at 45 d post pollination in the field or (2) fast FD vs. slow ear drying SD In laboratory. A field study across five locations compared HM, LM, FD, and SD strains from each of five synthetics for grain yield, ear moisture at harvest, test weight, lodging, and other agronomic traits. I studied ear moisture during grain filling for two subsets of divergently selected strains from one and three synthetics for 2 yr. In a third 2-yr field study, I measured mature kernel weight, lag period duration (LPD), effective grain-filling period (EFPD), and rate of dry matter accumulation (RDMA) for LM and HM strains developed from each of four synthetics. When averaged across the five synthetics, both SD and LM selections produced equivalent yields but lower ear moisture at harvest than the corresponding divergent strains. The LM strains had higher test weights than HM strains. When averaged across three synthetics and 2 yr, the HM strains produced higher moisture than LM strains at 15, 30, 45, and 60 d after silking. However, environments also influenced moisture content of the kernels during grain filling. In three of the four synthetics studied, HM strains had heavier kernels than corresponding LM strains. The heavier kernels seem to be due to increased RDMA. When averaged across four synthetics, LM strains had shorter LPD than HM strains. These correlated selection responses suggest that a genetic association exists among moisture content during grain filling, moisture content at physiological maturity, moisture content at harvest, LPD, and test weight. Breeding for LM or SD should improve field-drying characteristics of maize without increasing stalk breakage or decreasing yields. Key words:Zea mays L., grain filling, dry-down rates, mass selection, breeding methods

MASS SELECTION FOR POST-WEANING GROWTH IN SWINE. V. CORRELATED RESPONSE OF REPRODUCTIVE TRAITS AND PRE-WEANING GROWTH

1976 ◽  
Vol 56 (4) ◽  
pp. 791-801
Author(s):  
I. GARNETT ◽  
G. W. RAHNEFELD
Keyword(s):  
Birth Weight ◽  
Average Daily Gain ◽  
Reproductive Traits ◽  
Correlated Response ◽  
Mass Selection ◽  
Gestation Length ◽  
Control Line ◽  
Weaning Weight ◽  
Selection For ◽  
Daily Gain

Female reproductive performance and pre-weaning survival and growth were examined in a population of swine over 11 generations of selection for post-weaning average daily gain (ADG). Three separate breeding groups were used: (1) a Lacombe (L) line selected each generation for ADG, (2) a Yorkshire control (Y) line, and (3) a crossbred Lacombe × Yorkshire group (LY) generated each generation from the L and Y lines. Breeding group differences were evident for litter size, perinatal mortality, pre-weaning mortality, gestation length, birth weight, pre-weaning average daily gain (PreADG) and weaning weight. Selection did not affect number born, number born alive, number weaned or birth weight. When the values for the L line were expressed as a deviation from the control, pre-weaning mortality showed an increase. The increase appeared to be due to a decrease in the control rather than an increase in the L line. Gestation length showed a negative response to selection. As in the case of pre-weaning mortality, the response appeared to be a reflection of the instability of the control line. Genetic gains in PreADG of 0.004 kg/day/generation were realized in both the L line and LY group. Correspondingly, responses of 0.18 and 0.19 kg/generation were realized for weaning weight in the L line and LY group.

scholarly journals Kernel Changes in a Shrunken2 Maize Population Associated with Selection for Increased Field Emergence

1993 ◽  
Vol 118 (1) ◽  
pp. 135-140 ◽  
Author(s):  
John A. Juvik ◽  
Maurice C. Jangulo ◽  
John M. Headrick ◽  
Jerald K. Pataky ◽  
William F. Tracy
Keyword(s):  
Starch Content ◽  
Principal Component ◽  
Kernel Weight ◽  
Seedling Quality ◽  
Mass Selection ◽  
Principal Component Factor Analysis ◽  
Total Carbohydrate ◽  
Symptomatic Infection ◽  
Selection For ◽  
Field Emergence

Ten cycles of simple mass selection for increased field emergence and kernel weight in a population of shrunken2 (sh2) maize affected various kernel and seedling traits. Ten of 29 variables measured were intercorrelated and were included in the first principal factor of a principal component, factor analysis. The eight variables in factor 1 that increased with cycles of selection were: emergence and kernel weight (the two selection criteria) plant height 41 days after planting (a measure of seedling vigor), uniformity of stand, total starch content per kernel total carbohydrate content per kernel, concentration of starch, and starch content per kernel. The two variables in factor 1 that decreased were: conductivity of electrolytes that leached from imbibing seeds and symptomatic infection of kernels by fungi. Factor 1 was a “seed and seedling quality” factor. The other 19 variables formed five principal factors that primarily were “sugar,” “pericarp,” and “asymptomatic fungal infection” factors. These five factors and the variables from which they were formed, were not affected by selection. These results suggest that seed and seedling quality factors can be improved by selection in a sh2 population without affecting sweetness or tenderness. These results also suggest that although selection for increased emergence and kernel weight lowered the incidence of symptomatic infection by fungi, the population was not improved specifically for resistance to Fusarium moniliforme Sheldon.

MASS SELECTION FOR POSTWEANING GROWTH IN SWINE. III. CORRELATED RESPONSE IN WEANING WEIGHT AND FEED EFFICIENCY TO RECURRENT SELECTION FOR POSTWEANING AVERAGE DAILY GAIN IN SWINE

1973 ◽  
Vol 53 (2) ◽  
pp. 173-178
Author(s):  
G. W. RAHNEFELD
Keyword(s):  
Genetic Correlation ◽  
Feed Efficiency ◽  
Average Daily Gain ◽  
Direct Selection ◽  
Correlated Response ◽  
Mass Selection ◽  
Total Response ◽  
Weaning Weight ◽  
Selection For ◽  
Daily Gain

Correlated response in weaning weight and feed efficiency were estimated for a genetically variable population of swine selected during nine generations for postweaning average daily gain. Total response in weaning weight to direct selection for gain was 0.03 kg per generation. This was 3.1% of the predicted response. The estimate of genetic correlation between postweaning average daily gain and weaning weight was found high and positive (> 1). Total response in feed efficiency to direct selection for gain was −0.58 kg per generation. This was 10% of the predicted response. The estimate of genetic correlation between postweaning gain and feed efficiency was −0.35.

Associated changes in the attributes of wheat populations mass-selected for seed size

1973 ◽  
Vol 24 (2) ◽  
pp. 179
Author(s):  
GM Bhatt ◽  
NF Derera
Keyword(s):  
Seed Size ◽  
Kernel Hardness ◽  
Correlated Response ◽  
Mass Selection ◽  
Wheat Protein ◽  
Agronomic Characters ◽  
Economic Significance ◽  
Flour Protein ◽  
Protein Flour ◽  
Selection For

Evaluation of wheat populations mass-selected for seed size was made [or agronomical and quality characters in F2 and FQ generations of the crosses. Estimates of means and variances for these characters and their correlation with seed size were obtained to study the correlated response to selection for seed size. The expression of quality characters (test weight, milling extract, wheat protein, flour protein, and kernel hardness) was found to be independent of the expression of seed size in all the crosses studied. In the case of agronomic characters, however, the crosses behaved differently so far as the correlated response was concerned. It was concluded that in the crosses studied, mass selection for seed size could be practiced with certain associated advantages and without adverse response for most of the characters of economic significance in wheat.

scholarly journals SELECTION RESPONSE FOR INCREASED GRAIN YIELD IN TWO HIGH OIL MAIZE SYNTHETICS

2016 ◽  
Vol 8 (1) ◽  
pp. 1
Author(s):  
Made J. Mejaya ◽  
R.J. Lambert
Keyword(s):  
Grain Yield ◽  
Yield Components ◽  
Field Experiments ◽  
Selection Response ◽  
Kernel Weight ◽  
Grain Weight ◽  
Kernel Number ◽  
Starch Concentration ◽  
Oil Concentration ◽  
Selection For

Selection for increased oil level in maize showed the increase was associated with decrease in starch concentration, kernel weight, and grain yield. The study was conducted with the objectives: (1) to evaluate response to six cycles for increased grain yield in the high oil maize Alexho Elite (AE: 60-90 g kg-1 oil concentration) and Ultra High Oil (UHO: 100-140 g kg-1 oil concentration) using inbred tester B73; (2) to measure responses to selection for increased grain yield with changes in yield components; and (3) to determine a suitable tester. Previously the two synthetics had been selected for oil concentration. After six cycles, the six genotypes i.e. AE C0, AE C3, AE C6, UHO C0, UHO C3, and UHO C6 were testcrossed to B73, LH185, and LH202 inbreds (40 g kg-1 oil concentration) to a total of 18 testcrosses. Two field experiments were used to evaluate selection in AE and UHO testcrosses. The study showed selection using inbred tester B73 in AE and UHO was effective in increasing grain yield of AE testcrosses without changing (i.e. decreasing) oil and protein concentrations. AE testcrosses produced higher grain yield and greater selection response for grain yield than UHO testcrosses. LH185 was best for grain yield in AE and UHO testcrosses. Increase in grain yield in most of the testcrosses was associated with increases in starch concentration, kernel weight, kernel number, and grain weight.

scholarly journals SELECTION RESPONSE FOR INCREASED GRAIN YIELD IN TWO HIGH OIL MAIZE SYNTHETICS

2016 ◽  
Vol 8 (1) ◽  
pp. 1
Author(s):  
Made J. Mejaya ◽  
R.J. Lambert
Keyword(s):  
Grain Yield ◽  
Yield Components ◽  
Field Experiments ◽  
Selection Response ◽  
Kernel Weight ◽  
Grain Weight ◽  
Kernel Number ◽  
Starch Concentration ◽  
Oil Concentration ◽  
Selection For

Selection for increased oil level in maize showed the increase was associated with decrease in starch concentration, kernel weight, and grain yield. The study was conducted with the objectives: (1) to evaluate response to six cycles for increased grain yield in the high oil maize Alexho Elite (AE: 60-90 g kg-1 oil concentration) and Ultra High Oil (UHO: 100-140 g kg-1 oil concentration) using inbred tester B73; (2) to measure responses to selection for increased grain yield with changes in yield components; and (3) to determine a suitable tester. Previously the two synthetics had been selected for oil concentration. After six cycles, the six genotypes i.e. AE C0, AE C3, AE C6, UHO C0, UHO C3, and UHO C6 were testcrossed to B73, LH185, and LH202 inbreds (40 g kg-1 oil concentration) to a total of 18 testcrosses. Two field experiments were used to evaluate selection in AE and UHO testcrosses. The study showed selection using inbred tester B73 in AE and UHO was effective in increasing grain yield of AE testcrosses without changing (i.e. decreasing) oil and protein concentrations. AE testcrosses produced higher grain yield and greater selection response for grain yield than UHO testcrosses. LH185 was best for grain yield in AE and UHO testcrosses. Increase in grain yield in most of the testcrosses was associated with increases in starch concentration, kernel weight, kernel number, and grain weight.

MASS SELECTION FOR POSTWEANING GROWTH IN SWINE. VI. MEANS, HERITABILITIES, GENETIC AND PHENOTYPIC CORRELATIONS, AND CORRELATED RESPONSE OF CARCASS TRAITS

1983 ◽  
Vol 63 (1) ◽  
pp. 49-58 ◽  
Author(s):  
G. W. RAHNEFELD ◽  
R. L. CLIPLEF ◽  
I. GARNETT ◽  
R. M. McKAY
Keyword(s):  
Average Daily Gain ◽  
Carcass Traits ◽  
Correlated Response ◽  
Mass Selection ◽  
Correlated Responses ◽  
Phenotypic Correlations ◽  
Genetic And Phenotypic Correlations ◽  
Selection For ◽  
Color Score ◽  
Daily Gain

Means, heritabilities, genetic and phenotypic correlations, and correlated responses in carcass traits (total carcass backfat, carcass length, area 1. dorsi, ham weight, percentage ham of side, percentage lean in ham face, color score, texture score, and marbling score) during 11 generations of selection for postweaning average daily gain were studied on a selected Lacombe line, a Yorkshire control line, and a crossbred Lacombe × Yorkshire group generated each year from the two lines. With the exception of color score, the heritability estimates were moderate to high. Genetic and phenotypic correlations between average daily gain and the carcass traits ranged from − 0.16 to 0.46 and from − 0.07 to 0.15, respectively. Correlated responses in the carcass traits were very small. Key words: Swine, carcass traits, selection, heritabilities, correlations

Yield performance with heritability measurements of half sib families obtained from maize variety Azam

1970 ◽  
pp. 33-36
Author(s):  
Faizan Mahmood, Hidayat- Ur-Rahman, Nazir Ahmad ◽  
Fahim-ul- Haq ◽  
Samrin Gul, Quaid Hussain ◽  
Ammara Khalid ◽  
Touheed Iqbal ◽  
...  
Keyword(s):  
Grain Yield ◽  
Agronomic Traits ◽  
Heritability Estimate ◽  
Kernel Weight ◽  
Yield Performance ◽  
Grain Moisture ◽  
Maize Variety ◽  
Ear Height ◽  
Sib Families

This study evaluated the performance of 64 half sib families (HSF) derived from “Azam” variety of maize using partially balanced lattice square design with two replications. Data were recorded on grain yield and other agronomic traits. Observations showed difference in half-sib families for studied traits. Among the 64 half-sib families, minimum days to 50% tasseling (51 days) were observed for HS-49 while maximum (57 days) for HS-63. Minimum days to 50% silking (56 days) were counted for HS-6 while maximum (63 days) for HS-23. Minimum days to 50% anthesis (55 days) were counted for HS-1 and HS-6 while maximum (62 days) for HS-23. Similarly, minimum ASI (-2 days) were observed in HS-1, HS-15, HS-16, HS-28 and HS-63 while maximum (2 days) in HS-48. Minimum (60 cm) ear height was recorded for HS-11 and maximum (93.5 cm) for HS-28. Minimum fresh ear weight (1.3 kg) was weighted for HS-17 while maximum (3.2 kg) for HS-21. Grain moisture was recorded minimum (19.35 %) for HS-19 and maximum (31.25%) for HS-2. HS-42 showed minimum (28 g) 100 kernel weight while HS-5 showed maximum (47 g). Grain yield was minimum (2323 kg ha-1) for HS-17 and maximum (5742 kg ha-1) for HS-21. Maximum heritability estimate (0.92) was recorded for fresh ear weight, while minimum (0.41) was observed for ear height.

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