Husk Length Research Articles

Morphological characterization of sweet sorghum lines which has the potential as a raw material for bioethanol

Sweet sorghum is a potential plant as a raw material for bioethanol. This plant has the potential to be developed in tropical, semi-tropical and arid climates. To obtain information on elite lines as raw material for ethanol, it is necessary to characterize qualitative and quantitative traits. This study aims to obtain information about the quantitative and qualitative characters of several sweet sorghum lines that have the potential as raw materials for bioethanol. The research was carried out from August to December 2019 on the Experimental Farm of Indonesian Cereals Research Institute (ICERI), at Maros, South Sulawesi, Indonesia. The genetic materials used in this study were ten sweet sorghum lines, namely 15020B, 1115-C, 4-183ABEOTO, AB-6-1-1, EA-13-1-1, KL2, 10 (1-1), 23 (1-1), Buleleng Abang and WR2 and two varieties as check, namely Super-1 and Super-2, using a randomized block design in which genotype was the treatment factor. Qualitative data is explained by a descriptive method which refers to UPOV. Analysis of variance indicated significant differences in the quantitative and qualitative characters. Significantly different characters quantitatively were plant height, leaf length, leaf width, day to flowering, panicle length, and weight of 1000 grains. While the significant qualitative data are green leaf intensity, leaf bone color, pistil color, pistil length, dry stamen color, panicle shape, panicle density after pollination, self-pollination, husk color, husk length, grain color, seed shape, and endosperm texture. Based on morphological data, the promising elite lines as raw material for bioethanol were EA-13-1-1, KL2, WR2, Buleleng Abang, 61 (1-1) and 15020B. However, other scientific supporting data are needed to recommend superior sweet sorghum lines as raw material for bioethanol.

Determination of Pollinator Characteristics of Some Hazelnut Genotypes

This research was carried out in Karasu, Kocaali and Arifiye districts of Sakarya Province to determine the suitable pollinators for Çakıldak hazelnut cultivar (Corylus avellana) in 2021-2022. In the study, 27 genotypes that were late male flowering, formed a large amount of catkins, had high pollen quality, had round nut shape and short husk length were examined. Pollen viability was detected according to 2, 3, 5,-Triphenyl Tetrazolium Chloride (TTC). Pollen viability of the genotypes was ranged from 22.3% to 93.7% according to the TTC method. According to the agar method, pollen germination rate was determined between 15.6% and 78.1% at 20% sucrose concentration containing 1% agar. 89% of the genotypes were round, 11% were in the oblong nut group. It was determined that most of them amount of male inflorescences (catkins) depending on the tree crown volume and age. T-22KRS02, T-22KRS03, T-22KRS07, T-22KRS08, T-22KRS09, T-22KRS10, T-22KRS11, T-22KCL11, T-22KCL14, T-22KCL16 and Mincane were selected to be evaluated in the second phase of the study.

Molecular mapping of quantitative trait loci for 3 husk traits using genotyping by sequencing in maize (Zea mays L.)

The maize (Zea mays L.) husk consists of multiple leaf layers and plays an important role in grain growth and development. Despite significant achievements in physiological and morphological research, few studies have focused on the detection of genetic loci underlying husk-related traits due to the lack of efficient tools. In this study, we constructed an ultra-high-density linkage map using genotyping by sequencing based on a recombinant inbred line population to estimate the genetic variance and heritability of 3 husk traits, i.e. husk length, husk width, and husk layer number in 3 field environments and the combined environment. The 3 husk traits showed broad phenotypic variation and high heritability; the broad-sense heritability (H2) was 0.92, 0.84, and 0.86. Twenty quantitative trait loci were consistently detected more than 1 environment, including 9 for husk length, 6 for husk width, and 5 for husk layer number. These loci were considered as stable quantitative trait loci. Based on the quantitative trait loci mapping in the recombinant inbred line population, qHL6 and qHN4 were detected across all environments and inferred to be reliable and major-effect quantitative trait loci for husk length and husk layer number, respectively. In addition, several predicted candidate genes were identified in the region of qHL6 and qHN4, of which 17 candidate genes potentially play a role in biological processes related to development process and energy metabolism. These results will be as a useful resource for performing functional studies aimed at understanding the molecular pathways involved in husk growth and development.

Selection of Cape Gooseberry Based on Physical Variables of Their Fruit

Path coefficient analysis has been widely used to understand production better and determine the relationships between fruit and their constituents. This study evaluated the correlations between mass and other physical characteristics, and contributes to selecting cape gooseberry fruit. The attributes assessed were the total mass of the cape gooseberry fruit (TM) (fruit mass with husk), fruit mass (FM) (fruit mass without husk), husk mass (HM), husk length (HL), the largest transverse husk diameter (LD), fruit diameter (FD), and color of the husk (CH). Using path analysis, it was possible to verify directly that, among the physical components of the study, TM and FD have a direct and positive influence on FM. Fruit mass had a direct and negative correlation with HM, indicating that fruit with the heaviest husk (and green color) have not yet reached full maturation, nor reached their greatest mass. This result suggests that TM is strongly indirectly influenced by the HL, husk diameter, HM, and FD.

Genetic analysis of three maize husk traits by QTL mapping in a maize-teosinte population

BackgroundThe maize husk consists of numerous leafy layers and plays vital roles in protecting the ear from pathogen infection and dehydration. Teosinte, the wild ancestor of maize, has about three layers of small husk outer covering the ear. Although several quantitative trait loci (QTL) underlying husk morphology variation have been reported, the genetic basis of husk traits between teosinte and maize remains unclear.ResultsA linkage population including 191 BC2F8 inbred lines generated from the maize line Mo17 and the teosinte line X26–4 was used to identify QTL associated with three husk traits: i.e., husk length (HL), husk width (HW) and the number of husk layers (HN). The best linear unbiased predictor (BLUP) depicted wide phenotypic variation and high heritability of all three traits. The HL exhibited greater correlation with HW than HN. A total of 4 QTLs were identified including 1, 1, 2, which are associated with HL, HW and HN, respectively. The proportion of phenotypic variation explained by these QTLs was 9.6, 8.9 and 8.1% for HL, HN and HW, respectively.ConclusionsThe QTLs identified in this study will pave a path to explore candidate genes regulating husk growth and development, and benefit the molecular breeding program based on molecular marker-assisted selection to cultivate maize varieties with an ideal husk morphology.

Combining Ability of Husk Extension, Maysin Content, and Corn Earworm Resistance

Corn earworm (Helicoverpa zea) is a destructive pest with limited management options in sweet corn (Zea mays) production. Increased husk extension and the presence of the C-glycosyl flavone maysin are two proposed mechanisms for improving corn earworm resistance in corn cultivars. A factorial mating design was conducted to test hybrid combinations of sweet corn inbreds with long husks and/or maysin to identify candidates for future cultivar development. The mating design had seven male parents, including three commercial sweet corn inbreds (Wh9261, We11401, and Wt1001) and four inbreds selected for maysin content (Maysin1, 2, 3, and 4), and five female parents, including two commercial sweet corn inbreds (Ia453su and Ia5125su) and three inbreds with long, thick, tight husks (A684su, A685su, and A686su). Hybrids were evaluated for ear length, husk length, maysin content, and corn earworm resistance at six environments in 2016 and 2017. Relationships between husk extension, maysin, and corn earworm resistance were inconsistent, but five inbreds produced hybrids with significantly lower corn earworm infestation and/or damage, demonstrating potential to confer resistance to the corn earworm.

Genetic analysis of maize shank length by QTL mapping in three recombinant inbred line populations

In maize, the shank is a unique tissue linking the stem to the ear. Shank length (SL) mainly affects the transport of photosynthetic products to the ear and the dehydration of kernels via regulated husk morphology. The limited studies on SL revealed it is a highly heritable quantitative trait controlled by significant additive and additive-dominance effects. However, the genetic basis of SL remains unclear. In this study, we analyzed three maize recombinant inbred line (RIL) populations to elucidate the molecular mechanism underlying the SL. The data indicated the SL varied among the three RIL populations and was highly heritable. Additionally, the SL was positively correlated with the husk length (HL), husk number (HN), ear length (EL), and ear weight (EW) in the BY815/K22 (BYK) and CI7/K22 (CIK) RIL populations, but was negatively correlated with the husk width (HW) in the BYK RIL population. Moreover, 10 quantitative trait loci (QTL) for SL were identified in the three RIL populations, five of which were large-effect QTL. The percentage of the total phenotypic variation explained by the QTL for SL was 13.67 %, 20.45 %, and 30.81 % in the BY815/DE3 (BYD), BYK, and CIK RIL populations, respectively. Further analyses uncovered some genetic overlap between SL and EL, SL and ear row number (ERN), SL and cob weight (CW), and SL and HN. Unlike the large-effect QTL qSL BYK-2−2, which spanned the centromere, the other four large-effect QTL were delimited to a single peak bin via bin map. Furthermore, 2, 5, 6, and 12 genes associated with SL were identified for qSL BYK-2−1, qSL CIK-2−1, qSL CIK-9−1, and qSL CIK-9−2, respectively. Five of the candidate genes for SL may contribute to the hormone metabolism and sphingolipid biosynthesis regulating cell elongation, division, differentiation, and expansion. These results may be relevant for future studies on the genetic basis of SL and for the molecular breeding of maize based on marker-assisted selection to develop new varieties with an ideal SL.

Assessment of the Potential for Genomic Selection To Improve Husk Traits in Maize.

Husk has multiple functions such as protecting ears from diseases, infection, and dehydration during development. Additionally, husks comprised of fewer, shorter, thinner, and narrower layers allow faster moisture evaporation of kernels prior to harvest. Intensive studies have been conducted to identify appropriate husk architecture by understanding the genetic basis of related traits, including husk length, husk layer number, husk thickness, and husk width. However, marker-assisted selection is inefficient because the identified quantitative trait loci and associated genetic loci could only explain a small proportion of total phenotypic variation. Genomic selection (GS) has been used successfully on many species including maize on other traits. Thus, the potential of using GS for husk traits to directly identify superior inbred lines, without knowing the specific underlying genetic loci, is well worth exploring. In this study, we compared four GS models on a maize association population with 498 inbred lines belonging to four subpopulations, including 27 lines in stiff stalk, 67 lines in non-stiff stalk, 193 lines in tropical-subtropical, and 211 lines in mixture subpopulations. Genomic Best Linear Unbiased Prediction with principal components as cofactor, performed the best and was selected to examine the impact of interaction between sampling proportions and subpopulations. We found that predictions on inbred lines in a subpopulation were benefited from excluding individuals from other subpopulations for training if the training population within the subpopulation was large enough. Husk thickness exhibited the highest prediction accuracy among all husk traits. These results gave strategic insight to improve husk architecture.

Genome-Wide Association Study Dissects the Genetic Architecture of Maize Husk Tightness.

The husk is a leafy outer tissue that encloses a maize ear. Previously, we identified the optimum husk structure by measuring the husk length, husk layer number, husk thickness and husk width. Husk tightness (HTI) is a combined trait based on the above four husk measurements. Unveiling the genetic basis of HTI will aid in guiding the genetic improvement of maize for mechanical harvesting and for protecting the ear from pest damage and pathogen infection. Here, we used a maize associate population of 508 inbred lines with tropical, subtropical and temperate backgrounds to analyze the genetic architecture of HTI. Evaluating the phenotypic diversity in three different environments showed that HTI exhibited broad natural variations and a moderate heritability level of 0.41. A diversity analysis indicated that the inbred lines having a temperate background were more loosely related than those having a tropical or subtropical background. HTI showed significant negative correlations with husk thickness and width, which indicates that thicker and wider husks wrapped the ear tighter than thinner and slimmer husks. Combining husk traits with ∼1.25 million single nucleotide polymorphisms in a genome-wide association study revealed 27 variants that were significantly associated with HTI above the threshold of P < 7.26 × 10–6. We found 27 candidate genes for HTI that may participate in (1) husk senescence involving lipid peroxidation (GRMZM2G017616) and programmed cell death (GRMZM2G168898 and GRMZM2G035045); (2) husk morphogenesis involving cell division (GRMZM5G869246) and cell wall architecture (GRMZM2G319798); and (3) cell signal transduction involving protein phosphorylation (GRMZM2G149277 and GRMZM2G004207) and the ABSISIC ACID INSENSITIVE3/VIVIPAROUS1 transcription factor (GRMZM2G088427). These results provide useful information for understanding the genetic basis of husk development. Further studies of identified candidate genes will help elucidate the molecular pathways that regulate HTI in maize.

Genetic dissection of husk number and length across multiple environments and fine-mapping of a major-effect QTL for husk number in maize (Zea mays L.)

Husk number (HN) and husk length (HL) influence the mechanical harvesting of maize grain. We investigated the genetic basis of HN and HL using a population of 204 recombinant inbred lines phenotypically evaluated in five environments. The two husk traits showed broad phenotypic variation and high heritability. Nine stable quantitative trait loci (QTL) were identified by single-environment mapping, comprising four QTL for HN and five for HL, and three QTL explained >10% of the phenotypic variation. Joint mapping revealed 22 additive QTL and 46 epistatic QTL. Both additive and epistatic (additive × additive) effects as well as a few large-effect QTL and some minor-effect QTL appeared to contribute to the genetic architecture of HN and HL. The QTL for HN located on chromosome 7, qHN7, which accounted for ~20% of phenotypic variation, was detected in all five environments. qHN7 was fine-mapped to a 721.1 kb physical region based on the maize B73 RefGen_v3 genome assembly. Within this interval, four genes associated with plant growth and development were selected as candidate genes. The results will be useful for improvement of maize husk traits by molecular breeding and provide a basis for the cloning of qHN7.

Denser Markers and Advanced Statistical Method Identified More Genetic Loci Associated with Husk Traits in Maize

The husk—the leaf-like outer covering of maize ear—has multiple functions, including protecting the ear from diseases infection and dehydration. In previous studies, we genotyped an association panel of 508 inbred lines genotyped with a total of ~550,000 SNPs (Illumina 50 K SNP Chip and RNA-seq). Genome-Wide Association Studies (GWAS) were conducted on four husk traits: husk length (HL), husk layer number (HN), husk thickness (HT), and husk width (HW). Minimal associations were identified and none of them passed the P-value threshold after a Bonferroni multiple-test correction using a single locus test in framework of mixed linear model. In this study, we doubled the number of SNPs (~1,250,000 in total) by adding GBS and 600 K SNP Chip. GWAS, performed with the recently developed multiple loci model (BLINK), revealed six genetic loci associated with HN and HT above the Bonferroni multiple-test threshold. Five candidate genes were identified based on the linkage disequilibrium with these loci, including GRMZM2G381691 and GRMZM2G012416. These two genes were up-regulation and down-regulation in all husk related tissues, respectively. GRMZM2G381691 associated with HT encoded a CCT domain protein, which expressed higher in tropical than temperate maize. GRMZM2G012416 associated with HN encoded an Armadillo (ARM) repeat protein, which regulated GA signal pathway. These associated SNPs and candidate genes paved a path to understand the genetic architecture of husk in maize.

Linkage mapping combined with association analysis reveals QTL and candidate genes for three husk traits in maize.

Key message Combined linkage and association mapping analyses facilitate the emphasis on the candidate genes putatively involved in maize husk growth. The maize (Zea mays L.) husk consists of multiple leafy layers and plays important roles in protecting the ear from pathogen infection and in preventing grain dehydration. Although husk morphology varies widely among different maize inbred lines, the genetic basis of such variation is poorly understood. In this study, we used three maize recombinant inbred line (RIL) populations to dissect the genetic basis of three husk traits: i.e., husk length (HL), husk width (HW), and the number of husk layers (HN). Three husk traits in all three RIL populations showed wide phenotypic variation and high heritability. The HL showed stronger correlations with ear traits than did HW and HN. A total of 21 quantitative trait loci (QTL) were identified for the three traits in three RIL populations, and some of them were commonly observed for the same trait in different populations. The proportions of total phenotypic variation explained by QTL in three RIL populations were 31.8, 35.3, and 44.5% for HL, HW, and HN, respectively. The highest proportions of phenotypic variation explained by a single QTL were 14.7% for HL in the By815/K22 RIL population (BYK), 13.5% for HW in the By815/DE3 RIL population (BYD), and 19.4% for HN in the BYD population. A combined analysis of linkage mapping with a previous genome-wide association study revealed five candidate genes related to husk morphology situated within three QTL loci. These five genes were related to metabolism, gene expression regulation, and signal transduction.

Heritability, variance components and correlation of morphological and phenological traits in hazelnut

AbstractMost traits of interest in hazelnut are quantitative, yet there is little information available on heritability, variance components, or correlations. In this study, 13 morphological and four phenological traits were observed for 3 years on 41 parental genotypes, and for 2 years on seed‐lings representing 35 progenies. Narrow‐sense heritability estimates obtained by regression of offspring means on midparent values were all high, ranging from 0.56 for amount of kernel fibre to 0.89 for nut depth. Data on the parent genotypes was used to analyse variance components and showed that genotypic variance accounted for most of the phenotypic variance for all traits, and there was very little variation among trees within genotypes. Genotype‐year interaction accounted for only a very small part of the phenotypic variance for most traits, and changes in genotype rank were few and minor. Thus, selection based on genotype means is appropriate. The largest genotype‐year interaction components were observed for time of nut maturity, time of stigma exsertion, time of catkin elongation, number of nuts per cluster and amount of kernel fibre. For these five traits, evaluation over a period of years is advised. Correlation coefficients were large and positive for four nut size traits, indicating some redundancy in these measurements. Three of the phenological traits (time of stigma exsertion, time of catkin elongation, and time of leaf budbreak) were also highly and positively correlated. A large genetic correlation (0.44 &lt; r &lt; 0.73) was noted between good blanching and early phenology (catkin elongation, stigma exsertion and leaf budbreak), although plots of individual seedling values showed a large degree of scattering. Genetic correlations also indicated that seedlings with small nuts also tend to have compressed nuts, short husks and catkins that elongate later, but plots of individual seedling values showed large scattering. Correlations among the six traits directly related to the objectives of the Oregon State University hazelnut breeding programme (kernel weight, per cent kernel, nut shape index, blanching ability, relative husk length and nut maturity) were very low, indicating that they can be handled as independent traits.

Indirect Inbred Selection to Reduce Grain Moisture in Maize Hybrids

To select indirectly for low grain moisture in maize (Zea mays L.) hybrids, divergent lines were selected from two S2 populations on the basis of three morphological traits (date of husk senescence, husk length, and kernel number) that previously had been shown to be associated with faster drying rates in hybrids. Divergent lines were also selected on the basis of silking date. Nine hybrids for each selection classification were formed by crossing three selected S2 lines from one population with three inbreds, selected on the basis of the same criterion, from the second population. Field evaluation of the hybrids indicated that selection for early husk senescence in the inbreds decreased grain moisture by 27 g kg−1', hastened physiological maturity, and increased lodging in the associated hybrids. Selection for early husk senescence did not affect yield. Selection for the other three traits had no significant effect on grain moisture at harvest. Our results suggest that selection of early husk senescence in inbreds would result in hybrids with lower grain moisture and that evaluation of husk senescence may be useful in monitoring maturity in maize.

Inheritance of nut traits in filbert (Corylus avellana L.)

A filbert breeding program was initiated at Oregon State University in 1969 to develop improved cultivars for the Pacific Northwest. Nut traits were evaluated in parents and progenies and the first published inheritance data for this crop species are presented. Correlation coefficients of progeny means and mid-parent values are 0.92 for percent kernel, 0.84 for nut weight, 0.68 for amount of fiber on pellicle, 0.89 for kernel shrinkage, 0.70 for number of nuts per cluster, and 0.34 for estimated husk length. It is concluded that all but one of the evaluated traits is highly heritable and that additive gene action is principally responsible.

Resistance in Corn to the Corn Earworm and the Fall Armyworm. IV. Earworm Injury to Corn Inbreds Related to Climatic Conditions and Plant Characteristics1234

Correlations obtained between the means for 36 inbred Lines over 2 years indicated that only husk characters and feeding stimulation (among 14 characters measured) prodded reliable enough information to use in identifying plant genotypes resistant to injury by the corn car-worm. Heliothis zea (Boddie). Lines with husk length in excess of that required to cover the car tended to have more injury, but the mechanical protection of tight husks reduced damage considerably. Identification of genotypes with resistance unrelated to husk characters appears possible through laboratory evaluations of the feeding stimulation caused by extracts of kernels. These results suggest that resistance is conditioned by both physical and chemical factors. Relationships between other characters and corn earworm injury fluctuated widely from year to year.