Soft White Spring Wheat Research Articles

Quantitative proteomic analysis of super soft kernel texture in soft white spring wheat.

Super soft kernel texture is associated with superior milling and baking performance in soft wheat. To understand the mechanism underlying super soft kernel texture, we studied proteomic changes between a normal soft and a super soft during kernel development. The cultivar 'Alpowa', a soft white spring wheat, was crossed to a closely related super soft spring wheat line 'BC2SS163' to produce F6 recombinant inbred lines (RILs). Four normal soft RILs and four super soft RILs along with the parents were selected for proteomic analysis. Alpowa and the normal soft RILs showed hardness indices of 20 to 30, whereas BC2SS163 and the super soft RILs showed hardness indices of -2 to -6. Kernels were collected from normal soft and super soft genotypes at 7 days post anthesis (dpa), 14 dpa, 28 dpa, and maturity and were subject to quantitative proteomic analysis. Throughout kernel development, 175 differentially abundant proteins (DAPs) were identified. Most DAPs were observed at 7 dpa, 14 dpa, and 28 dpa. Of the 175 DAPs, 32 had higher abundance in normal soft wheat, whereas 143 DAPs had higher abundance in super soft wheat. A total of 18 DAPs were associated with carbohydrate metabolism and five DAPs were associated with lipids. The gene TraesCS4B02G091100.1 on chromosome arm 4BS, which encodes for sucrose-phosphate synthase, was identified as a candidate gene for super soft kernel texture in BC2SS163. This study enhanced our understanding of the mechanism underlying super soft kernel texture in soft white spring wheat.

Missense alleles of the HMW glutenin subunits Dx5 and Dy10 have small changes in function relative to missense changes in Puroindoline a and b

AbstractBackground and ObjectivesThe high molecular weight glutenin subunit genes (HMW‐GS) in wheat (Triticum aestivum L.) play a key role in determining dough functionality. More specifically allelic variation for the Glu‐D1 subunit loci is consistently associated with bread making quality. Since much of the hard wheat germplasm is fixed for the more favorable 1Dx5 + 1Dy10 haplotype, our goal was to identify allelic variation in 1Dx5 and 1Dy10 HMW‐GS genes using an ethyl methanesulfonate (EMS) mutagenized population in the soft white spring wheat cultivar “Alpowa.” The same source population was previously used in screening for creating novel alleles in Puroindoline a (Pina) and Puroindoline b (Pinb) which are responsible for grain hardness variation. Direct sequencing of 384 M3 families identified 135 point mutations equally dispersed across 1Dx5 and 1Dy10. The mutation discovery rate was 1/12.7 kb of DNA, equal to that found in the Pin loci. Mutation carrying plants were crossed to the nonmutagenized Alpowa parent to create F2 populations segregating for the induced EMS HMW Glutenin mutations. Swelling index of gluten (SIG) was measured from seed from field grown plants to assess the impact of each EMS mutation upon Glutenin function.FindingsNonsense mutations in both 1Dx5 and 1Dy10 reduced SIG values, indicating both 1Dx5 and 1Dy10 are needed for gluten functionality. Missense mutations did not alter SIG values compared to their wild type counterparts. In contrast missense mutations within the tryptophan‐rich region of both PINS increased grain hardness pointing to the importance of this protein region. No such region in 1Dx5 or 1Dy10 was found indicating these proteins are structurally stable and tolerant of amino acid substitution.ConclusionsResults from the Glu‐D1 subunit and Pin loci show that useful phenotypic variation can be created using EMS mutagenesis for genes where naturally occurring mutations occur from amino substitutions as is the case for the Pin loci.Significance and NoveltyEMS induced mutations are useful for creating new alleles in storage proteins with much greater impacts in genes that have a defined active site as for the Pin loci than in genes such as the HMW Glu‐1 genes which have a long repetitive region.

Wheat yield and protein estimation with handheld‐ and UAV‐based reflectance measurements

AbstractPrecision agriculture provides efficient means of obtaining real‐time data to guide nitrogen (N) management based on predicted crop profitability. This study was conducted to assess the efficacy of using in‐season measurements (plant height, biomass weight, biomass N, soil plant analysis development [SPAD], GreenSeeker [GS] normalized difference vegetative index [NDVI], and unmanned aerial vehicle [UAV] NDVI) at Feekes 5 (tillering) and Feekes 10 (anthesis) to estimate wheat (Triticum aestivum L.) yield and protein. The secondary aim was to determine whether the accuracy of yield and protein prediction varies by wheat class and cultivar. Six cultivars—hard red spring (HRS) wheat ‘Jefferson’ and ‘SY Basalt’, hard white spring (HWS) wheat ‘Dayn’ and ‘UI Platinum’, and soft white spring (SWS) wheat ‘Seahawk’ and ‘UI Stone’—were planted at two locations in Idaho in 2018–2020. Plots were arranged in a randomized complete block design with four replications with each cultivar evaluated at seven N rates (0, 50, 100, 150, 200, 250, and 300 kg N ha–1). The determination of the Pearson correlation coefficients revealed that all parameters were linearly correlated with yield except for SPAD at Feekes 5 and biomass weight at Feekes 10. Although estimation of in‐season grain protein remains a challenge, NDVI was strongly correlated with yield especially at Feekes 5. The accuracy of yield prediction was similar for all wheat classes. Comparable accuracy of yield estimation was achieved with GS NDVI and UAV NDVI. Both hand‐held and aerial‐based spectral measurements could be used to prescribe N rates to be applied during tiller formation when wheat yield can be optimized.

AAC Paramount soft white spring wheat

AAC Paramount is a soft white spring wheat (Triticum aestivum L.) cultivar that meets the end-use quality specifications of the Canada Western Soft White Spring (CWSWS) class. AAC Paramount is adapted to the irrigated wheat growing regions of southern Alberta and southern Saskatchewan, and for dry land production in the western prairies. On average, AAC Paramount had 6% higher grain yield (under both irrigated and dry land conditions) than the check cultivar AC Andrew. AAC Paramount exhibited excellent straw strength and similar maturity to AC Andrew and Sadash but was 2 d earlier than AAC Indus. Its plant height was taller than both AC Andrew and Sadash but similar to AAC Indus. AAC Paramount exhibited high levels of resistance to the prevalent races of stripe rust, powdery mildew, and loose smut; intermediate reactions to leaf rust, stem rust, and kernel black point; was moderately susceptible to Fusarium head blight and leaf spot diseases, and susceptible to common bunt.

Investigating conditions that induce late maturity alpha-amylase (LMA) using Northwestern US spring wheat (Triticum aestivum L.)

AbstractThe wheat industry rejects grain with unacceptably high α-amylase enzyme levels due to the risk of poor endproduct quality. There are two main causes of elevated grain α-amylase: (1) preharvest sprouting in response to rain before harvest and (2) late maturity α-amylase (LMA) induction in response to a cool temperature shock during late grain development. LMA induction was detected in a panel of 24 Northwestern US spring wheat lines. Thus, this problem previously described in Australian and U.K. varieties also exists in U.S. varieties. Because LMA induction results were highly variable using published methods, a characterization of LMA-inducing conditions was conducted in an LMA-susceptible soft white spring wheat line, WA8124. Problems with elevated α-amylase in untreated controls were reduced by raising the temperature, 25°C day/18°C night versus 20°C day/10°C night. LMA induction was not improved by colder temperatures (15°C day/4°C night) versus moderately cold temperatures (18°C day/7.5°C night or 10°C day/10°C night). While previous studies observed LMA induction by heat stress, it failed to induce LMA in WA8124. Thus, not all LMA-susceptible cultivars respond to heat. The timing of LMA susceptibility varied between two cultivars and within a single cultivar grown at slightly different temperatures. Thus, variability in LMA induction likely results from variability in the timing of the grain developmental stage during which cold shock induces LMA. Thus, it was concluded that the visual inspection of grain is needed to correctly identify LMA-sensitive spikes at the soft dough stage of grain development (Zadok's stage 85).

Registration of ‘USDA Lori’ soft white spring waxy wheat

AbstractStarch is the most abundant component of wheat (Triticum spp.) grain and flour and is composed of two primary glucose polymers, amylose and amylopectin. Our aim was to convert a previously leading soft white spring wheat (T. aestivum L.) cultivar to a zero endosperm starch amylose content (“waxy”) cultivar. The result was ‘USDA Lori’ (Reg. no. CV‐1180, PI 692132), a waxy wheat cultivar developed by the USDA Agricultural Research Service's Western Wheat Quality Laboratory in collaboration with Washington State University. USDA Lori is a backcross‐7 (BC7) derivative of ‘Alpowa’. USDA Lori lacks functional copies of the three Waxy Granule Bound Starch Synthase I (GBSSI) genes. The GBSSI null alleles were derived from the waxy cultivar ‘Waxy‐Pen’. As a waxy cultivar, USDA Lori has unique processing and food and feed applications. Further, this waxy cultivar complements a series of Waxy near‐isogenic lines, which were produced as backcross derivatives of Alpowa.

Registration of the Louise‐Penawawa spring wheat recombinant inbred line mapping population

AbstractThe Louise‐Penawawa spring wheat (Triticum aestivum L.) recombinant inbred line (RIL) mapping population (Reg. no. MP‐13, NSL 535038 MAP) was developed from a cross between the elite soft white spring wheat cultivars ‘Louise’ and ‘Penawawa’ at Washington State University. The population is composed of 180 RILs developed through single seed descent from the F2 to the F5 generation. The population and its parents were genotyped using both simple sequence repeat and single‐nucleotide polymorphism marker platforms. Analysis of markers identified 29 linkage groups that located to all 21 wheat chromosomes. The population was initially developed for the study of high‐temperature adult‐plant stripe rust resistance but has since been phenotyped and used to identify Hessian fly resistance, tan spot resistance, polyphenol oxidase activity, vital agronomic traits, and milling and baking quality. Markers have been identified that are closely linked with quantitative trait loci (QTL) that influence these traits. This population has the potential to identify QTL for additional traits of interest. Additionally, lines from this RIL population are well suited to introgress traits of interest as both Louise and Penawawa are commercially released cultivars adapted to a variety of growing regions and conditions.

Registration of extra‐hard kernel near‐isogenic hexaploid wheat genetic stocks lacking puroindoline genes

AbstractKernel hardness (texture) is a key end‐use quality trait of wheat (Triticum spp.). Two hexaploid wheat (T. aestivum L.) near‐isogenic lines (NILs), WQL18RE5 (Reg. no. GS‐190, PI 691609) and WQL18CS5 (Reg. no. GS‐191, PI 691610), lack the puroindoline genes at the Hardness locus and thus have kernel texture phenotypes more similar to durum wheat [T. turgidum subsp. durum (Desf.) Husn.]. These two genetic stocks were produced in ‘Alpowa’ soft white spring wheat and comprise additions to an ongoing series of NILs in this soft wheat cultivar. Both NILs are advanced generation BC7F2:5 derivatives (Alpowa/donor/7*Alpowa). WQL18RE5 was derived from a Chinese Spring (CS) disomic substitution line, CS (Red Egyptian 5D), and WQL18CS5 was derived from a CS deletion line (CS5DS del.‐2) that lacks the distal portion of the short arm of chromosome 5D. These lines were developed at the USDA‐ARS Western Wheat Quality Laboratory and will be useful to study kernel texture and end‐use quality in hexaploid wheat; they can also serve as parents in developing cultivars with kernel texture equivalent to that of durum wheat.

Re-evolution of Durum Wheat by Introducing the Hardness and Glu-D1 Loci

Durum wheat is an important crop worldwide. In many areas, durum wheat appears to have competitive yield and biotic and abiotic advantages over bread wheat. What limits durum production? In one respect, the comparatively more limited processing and food functionality. Two traits directly relate to these limitations: kernel texture (hardness) and gluten strength. We have addressed both using ph1b-mediated translocations from bread wheat. For kernel texture, ca. 28 Mbp of chromosome 5DS replaced about 20 Mbp of 5BS. SKCS hardness was reduced from ca. 80 to 20 as the puroindolines were expressed and softened the endosperm. Break flour yields increased from 17% to >40%. Straight-grade flour had low starch damage (2%), and a mean particle size of 75 µm. Crosses with CIMMYT durum lines all produced soft kernel progeny and a high degree of genetic variance for milling and baking quality. Solvent Retention Capacities (SRC) and cookie diameters were similar to soft white hexaploid wheat, showing that soft durum can be considered a “tetraploid soft white spring wheat”. Regarding gluten strength, CIMMYT durums contributed a high genetic variance, with the “best” progeny exhibiting SDS sedimentation volume, SRC Lactic Acid and Mixograph characteristics that were similar to medium-gluten strength U.S. hard red winter. The best loaf volume among these progeny was 846 cm3 at ca. 12.8% flour protein. To further address the issue of gluten strength, Soft Svevo was crossed with durum lines possessing Dx2+Dy12 and Dx5+Dy10. Bread baking showed that Dx5+Dy10 was overly strong, whereas Dx2+Dy12 significantly improved bread loaf volume. The best progeny produced a loaf volume of 1010 cm3 at 12.1% protein. As a comparison, the long-term in-house regression for loaf volume-flour protein for hard red ‘bread’ wheats is 926 cm3 at 12.1% protein. Obviously, from these results, excellent bread making potential has been achieved.

Differential Nitrogen and Water Impacts on Yield and Quality of Wheat Classes

High wheat (Triticum aestivum L.) grain yield and desirable quality must be considered to avoid market price penalty. Wheat classes and genotypes may respond differently to agronomic management and environmental conditions. Our goal was to characterize the yield, protein, test weight, and falling number of four hard red and four soft white spring wheat cultivars randomized within the five N levels over contrasting environments (rainfed and irrigated) in northwestern Montana. One‐third yield reduction from 2016 to 2017 was attributed to heat stress. Irrigation increased both grain yield and test weight. However, falling number was generally higher under rainfed environment, but was also cultivar dependent. ‘Egan,’ ‘McNeal,’ and ‘Alpowa’ falling number values were more resilient to environmental differences than other cultivars. Overall, soft whites had higher yields than hard reds, but with a stronger negative yield to protein relationship. Achieving high yield in hard reds via irrigation did not reduce grain protein in relation to rainfed, except at very low N (2017 control). The cultivar Egan, with Gpc‐B1 gene for higher grain protein, had similar yield to its parent material and to other hard red, though inferior to ‘Vida’ (characterized by extended green leaf duration after heading) under hot and dry conditions. During the less limiting year (2016), the maximum protein was achieved with much less N under irrigated environment compared with rainfed. Soft whites, due to lower grain protein requirement and lack of yield response to N in our study, can be grown with lower N input than hard reds.Core Ideas Egan (Gpc‐B1 gene cultivar) had superior grain protein with relatively no yield penalty Vida (stay‐green trait cultivar), Alturas, and UI Stone are more resilient under varied growing conditions and management Soft white market class had higher grain yield and stronger protein dilution than hard red

Registration of Wheat Lines Carrying Novel Mutagenesis‐Derived Puroindoline Alleles

Grain texture is an important factor in determining milling properties of wheat (Triticum aestivum L). Grain texture is mainly controlled by two tightly linked genes, Puroindoline a (Pina) and Puroindoline b (Pinb). The goal of this research was to further characterize and release near isolines for novel Puroindoline alleles with unique levels of grain hardness. Seed of soft white spring wheat ‘Alpowa’ was treated with ethyl methanesulfonate (EMS). The Pin genes were amplified by polymerase chain reaction and then sequenced, after which missense mutations in both Pina and Pinb were identified. Seven novel alleles were backcrossed twice to the Alpowa parent to produce BC2F2–derived near isolines: MT363‐4 (Reg. No. GP‐1033, PI 689449), MT421‐27 (Reg. No. GP‐1034, PI 689450), MT777‐14 (Reg. No. GP‐1035, PI 689451), MT1306‐19 (Reg. No. GP‐1036, PI 689452), MT1899‐9 (Reg. No. GP‐1037, PI 689453), MT2092‐42 (Reg. No. GP‐1038, PI 689454), and MT2252‐14 (Reg. No. GP‐1039, PI 689455). One was softer than its wild type (MT2092‐42 [PINA‐R103K/PINBa]), three had intermediate hardness (51 to 54 hardness units using the single kernel characterization system) (MT363‐4 [PINA‐P35S/PINBa]; MT1306‐19 [PINA‐G47S/PINBa]; MT1899‐9 [PINAa/PINB‐D34N]), and three were hard (>65 hardness units) (MT421‐27 [PINAa/PINB‐T38I]; MT777‐14 [PINAa/PINB‐G46D]; and MT2252‐14 [PINAa/PINB‐E51K]). Kernel weight, grain protein, and test weight for the novel alleles did not differ from their wild‐type counterparts. Some of the novel alleles provide grain hardness values outside the range of naturally occurring Pin alleles, while others provide unique PIN proteins, giving haplotype diversity at these loci.

Milling and baking quality of hexaploid spring wheat starch synthase IIa (ssIIa) mutants with elevated amylose content

AbstractBackground and objectivesNovel alleles of starch synthase II (ssIIa) homeologs were created in a soft white spring wheat using chemical mutagenesis and then combined to create four unique ssIIa triple mutant haplotypes. Previous research found the resultant triple ssIIa mutants were hard in texture and had increased seed amylose and protein content that was strongly correlated with decreases in individual seed weight and seed starch content. The objective of this research was to examine how these changes in amylose content affect milling and bread baking characteristics.FindingsTriple ssIIa mutant haplotypes yielded significantly less flour that had a higher protein and ash content, decreased brightness, and increased yellowness and redness compared to controls. Solvent retention capacity tests on flour from ssIIa mutant lines had significant increases in water, sucrose, and sodium bicarbonate absorption but similar lactic acid absorption and poor gluten performance indexes compared to controls. Flour dough made from ssIIa mutants had increased water absorption with increased mixing tolerance and produced bread with significantly reduced loaf volume, crumb grain score, and crumb brightness with increased crumb yellowness and redness. Attempts to restore loaf volume using up to 6% vital wheat gluten were unsuccessful.ConclusionsHigh amylose ssIIa triple mutants have significant decreases in flour yields as a result of their diminished starch content and seed size. The unique composition of flour from ssIIa triple mutants does not readily lend itself to producing a functional dough for bread making and resultant bread has significant decreases in loaf volume.Significance and noveltyOur results demonstrate that flour with increased amylose levels can be used to create bread with increased protein and dietary fiber.

Reduction of falling number in soft white spring wheat caused by an increased proportion of spherical B-type starch granules

A low falling number (FN) in wheat indicates high α-amylase activity associated with poor end-use quality. We hypothesize starch – the substrate of α-amylase, can directly influence hot flour pasting properties and its susceptibility to α-amylase, which further affects viscosity. We examined the structural characteristics of starch in three soft white spring wheat cultivars grown in Idaho in 2013 (normal FN year) and 2014 (low FN year with pre-harvest rains). Our data surprisingly show that starch in some low FN wheat was not significantly degraded by α-amylase but had developmental changes with an increased proportion of B-type wheat starch. We reconstituted wheat starch and verified that starch with an increase of B-granules has a relatively low viscosity and high susceptibility to wheat α-amylase, which further facilitates the decrease of viscosity. The influence of starch structure and starch-enzyme interaction must be considered while developing a solution to the low FN issue.

Genetic analysis of a unique ‘super soft’ kernel texture phenotype in soft white spring wheat

Kernel texture is a key determinant of flour quality. Herein, a population of 125 recombinant inbred lines (RILs) was developed from a cross between the spring wheat cultivar Alpowa (normal soft) and a closely related uniquely ‘super soft’ line. To study the genetic variation for kernel texture, the RILs and parents were genotyped using high-density single nucleotide polymorphism (SNP) markers. Polymorphic markers (n = 1425) were used for genetic mapping and 372 non-redundant markers were assembled on 21 linkage groups covering 14 chromosomes. Ten QTLs were identified for kernel texture using composite interval mapping (CIM), including four major QTLs on 1BS, 4BS, 5AL and 7AS. Single marker-trait association was also carried out using the same set of markers (1425), and 339 significant markers were identified for kernel texture. Of these 339 markers, the ten best markers, which included the four QTLs above each accounted for 15.0–19.3% phenotypic variation. None of the kernel texture QTL co-located with QTLs for kernel weight or kernel size. This study shows the complex inheritance of this unique super soft kernel trait. Nevertheless, the trait is heritable and could be used to provide bakers a new type of flour.

Registration of the Louise/Alpowa Wheat Recombinant Inbred Line Mapping Population

A mapping population was developed from the cross of soft white spring wheat (Triticum aestivum L.) cultivars ‘Louise’ and ‘Alpowa’ for use in investigating the genetic architecture of drought tolerance in the US Pacific Northwest. The Louise/Alpowa (Reg. No. MP‐8, NSL 520824 MAP) recombinant inbred line mapping population was developed through single seed descent from the F2 generation to the F5 generation. The population consists of 141 F5:6 recombinant inbred lines, of which 132 were used to construct the genetic linkage map. The 32 linkages groups included 882 single nucleotide polymorphism markers and one simple sequence repeat marker spanning 18 of 21 chromosomes. The Louise/Alpowa population was characterized for variation in agronomic traits, phenology, and end‐use quality traits. This population will be used for identification and introgression of multiple loci providing resistance to environmental stress such as drought, stripe rust, and high temperatures.

Irrigated soft white spring wheat is largely unresponsive to conservation management in rotations with dry bean, potato and sugar beet

Historically, soft white spring (SWS) wheat (Triticum aestivum L.) has been a crop choice in southern Alberta’s irrigation districts. A 12-yr (2000–2011) study compared conservation (CONS) and conventional (CONV) management for SWS wheat in 3–5-yr rotations with dry bean (Phaseolus vulgaris L.), potato (Solanum tuberosum L.), and sugar beet (Beta vulgaris L.). Conservation management incorporated reduced tillage, compost, cover crops, and narrow-row dry bean. Wheat was largely unresponsive to CONS management, with only 2 of 13 parameters showing significant positive effects: greater grain Ca (605 vs. 576 μg g−1 on CONV) and S concentrations (1137 vs. 1105 μg g−1 on CONV). Two parameters showed significant negative responses to CONS management: shorter plant height (82.8 vs. 84.8 cm on CONV) and higher take-all [Gaeumannomyces graminis (Sacc.) Arx & Olivier var. tritici Walker] severity (1.34 vs. 1.27 rating on CONV). The remaining nine parameters were unresponsive: plant density, days to maturity, grain y...

Adapting the nitrogen replacement approach to dryland spring wheat in the Pacific Northwest

The objective of this article is to summarize results of a study conducted in eastern Oregon to define the critical protein levels for dark northern spring and soft white spring wheats and their fertilizer nitrogen equivalent values. Earn 1 CEU in Nutrient Management by reading this article and taking the quiz at www.certifiedcropadviser.org/education/classroom/classes/494.

Identification of SNPs, QTLs, and dominant markers associated with wheat grain flavor using genotyping-by-sequencing

Consumer acceptance of whole wheat products can be hindered by the flavor, aroma, and texture. A laboratory mouse model system was used to examine flavor using a two-choice feeding system employing a common check variety and the Student's t statistic as a consumption phenotype. Samples were from a doubled haploid population derived from “Yummy” (Louise) and “yucky” (Yumai34) soft white spring wheat parents. Genotyping-by-sequencing (GBS) identified 655 single nucleotide polymorphic (SNP) markers that differed between the two parents, which were used to create a genetic map with 24 linkage groups. Thirty-nine SNP markers exhibited a significant marker-trait association with consumption, and four significant QTL were detected. Additionally, a novel approach that identified dominant markers successfully found both Louise- and Yumai34-dominant GBS sequence tags. The Louise-dominant markers exhibited high levels of marker-trait association with the Student's t statistic flavor preference phenotype. In total, markers mapped to seven genic regions. In particular, dominant markers on 4DL exhibited the greatest F-values and provided the strongest evidence that genes involved in wheat flavor were located there. This work furthers the understanding of the genetics involved in wheat grain flavor and will aid in the development of varieties with greater consumer acceptance for whole-wheat products.

Sugar beet response to rotation and conservation management in a 12-year irrigated study in southern Alberta

Sugar beet (Beta vulgaris L.) has a long history as an option for irrigated crop rotations in southern Alberta. A 12-yr (2000–2011) study compared conservation (CONS) and conventional (CONV) management for sugar beet in 4- to 6-yr rotations which also included dry bean (Phaseolus vulgaris L.), potato (Solanum tuberosum L.), and soft white spring wheat (Triticum aestivum L.). Oat (Avena sativa L.) and timothy (Phleum pratense L.) were included in the longest 6-yr rotation. Conservation management incorporated reduced tillage, cover crops, feedlot manure compost addition, and solid-seeded dry bean. Compared with a 4-yr CONV rotation (52.2 Mg ha−1), sugar beet root yield (averaged over the second 6 yr of the study, 2006–2011) was significantly higher, by 11%, on 4- and 5-yr CONS rotations (57.7–57.9 Mg ha−1), and by 8% on a 6-yr CONS rotation (56.1 Mg ha−1). Sugar beet impurity parameters were significantly affected by rotation in, at most, 3 of 12 yr. However, averaged over the final 6 yr of the study (2006–2011), a significantly higher K concentration (impurity) was found with CONS (2108 mg kg−1) vs. CONV (1958 mg kg−1) management. Integrating CONS management practices into sugar beet rotations led to significant yield benefits while effects on sugar beet quality were minimal.

The wheat ABA hypersensitive ERA8 mutant is associated with increased preharvest sprouting tolerance and altered hormone accumulation

Wheat preharvest sprouting (PHS) is the germination of mature grain on the mother plant when rain occurs before harvest. Higher abscisic acid (ABA) hormone levels and sensitivity are associated with higher seed dormancy and PHS tolerance. Consistent with this, the ABA hypersensitive ENHANCED RESPONSE TO ABA8 (ERA8) mutant resulted in increased dormancy and PHS tolerance in soft white spring wheat ‘Zak’. ERA8 seeds were initially less responsive to germination-rescue by the hormone gibberellin (GA). ERA8 gained GA and lost ABA sensitivity more slowly than wild-type during dormancy loss through after-ripening and cold imbibition. This study examined if increased ABA sensitivity in ERA8 likely resulted from increased ABA signaling or increased ABA hormone levels. Zak ERA8 had higher initial grain dormancy although endogenous embryo ABA levels were similar in Zak ERA8 and wild-type, suggesting that increased dormancy was due to increased ABA signaling rather than increased ABA accumulation. ABA levels declined with Zak ERA8 after-ripening, suggesting that ABA turnover is not defective. Elevated ERA8 dormancy was also associated with increased embryonic jasmonic acid-Ile and aleurone indole-3-acetic acid (IAA) levels. The possible implication that other plant hormones may influence wheat seed dormancy and germination are discussed.