S. P. Lanning

Enhanced ADP-glucose pyrophosphorylase activity in wheat endosperm increases seed yield

Yield in cereals is a function of seed number and weight; both parameters are largely controlled by seed sink strength. The allosteric enzyme ADP-glucose pyrophosphorylase (AGP) plays a key role in regulating starch biosynthesis in cereal seeds and is likely the most important determinant of seed sink strength. Plant AGPs are heterotetrameric, consisting of two large and two small subunits. We transformed wheat (Triticum aestivum L.) with a modified form of the maize (Zea mays L.) Shrunken2 gene (Sh2r6hs), which encodes an altered AGP large subunit. The altered large subunit gives rise to a maize AGP heterotetramer with decreased sensitivity to its negative allosteric effector, orthophosphate, and more stable interactions between large and small subunits. The Sh2r6hs transgene was still functional after five generations in wheat. Developing seeds from Sh2r6hs transgenic wheat exhibited increased AGP activity in the presence of a range of orthophosphate concentrations in vitro. Transgenic Sh2r6hs wheat lines produced on average 38% more seed weight per plant. Total plant biomass was increased by 31% in Sh2r6hs plants. Results indicate increased availability and utilization of resources in response to enhanced seed sink strength, increasing seed yield, and total plant biomass.

Assessing Environmental Influences on Solvent Retention Capacities of Two Soft White Spring Wheat Cultivars

ABSTRACT The solvent retention capacity test (SRC) (AACC Approved Method 56-11) of flour is used to evaluate multiple aspects of wheat (Triticum aestivum L.) quality including pentosan content, starch damage, gluten strength, and general water retention based on the ability of flour to retain a range of solvents. The objectives of this study were to evaluate the effects of grain production environment in general and crop irrigation and fertility management in particular on SRC of soft wheat flour, and to evaluate the ability of SRC to predict end-use quality across diverse environments. Two soft white spring wheat cultivars ‘Pomerelle’ and ‘Centennial’ were produced in a range of irrigated and rain-fed production environments. SRC profiles and milling and baking quality parameters were measured. In a two-year study at Aberdeen, ID, with two late-season irrigation management regimes and two crop nitrogen fertility treatments, only wheat genotype significantly affected flour SRC. In two-year studies at Teto...

Relationship of Dough Extensibility to Dough Strength in a Spring Wheat Cross

ABSTRACT A negative relationship between dough strength and dough extensibility would pose a problem for breeding hard wheats, as both dough strength and dough extensibility are desirable. We derived 77 recombinant inbred lines (RIL) from a cross between hard red spring wheat cultivars McNeal and Thatcher. McNeal produces flour with stronger dough and lower extensibility than does Thatcher. RIL were evaluated for strength-related properties using mixograph analysis and extensibility parameters using the Kieffer attachment to the TA.XT2 texture analyzer. Additionally, the RIL were test baked. Measurements using the mixograph and the Kieffer attachment were highly heritable. Maximum dough extensibility (Extmax) was negatively correlated with resistance to extension (Rmax) (r = -0.74) and with mixograph tolerance (r = -0.45). Loaf volume was correlated with both Rmax (r = 0.42) and area under the extensigraph curve (r = 0.44) based on partial correlation analysis adjusted for protein differences. Extmax was ...

Reduced Amylose Effects on Bread and White Salted Noodle Quality

ABSTRACT Amylose content in wheat endosperm is controlled by three Wx loci, and the proportion of amylose decreases with successive accumulation of Wx null alleles at the three loci. The proportion of amylose is believed to influence end-use quality of bread and Asian noodles. The objectives of this study were to determine influence of the allelic difference at Wx-B1 locus on bread quality, bread firmness, and white salted noodle texture in a spring wheat cross segregating for the Wx-B1 locus and in a set of advanced spring wheat breeding lines differing in allelic state at the Wx- B1 locus. In addition, we examined the relationship between amylose content and flour swelling properties on bread and noodle traits. Fifty-four recombinant inbred lines of hard white spring wheat plus parents were grown in replicated trials in two years, and 31 cultivars and breeding lines of hard spring wheat were grown in two locations. Bread and white salted noodles were processed from these trials. The presence of the Wx-B...

Effect of Variation in Amylose Content and Puroindoline Composition on Bread Quality in a Hard Spring Wheat Population

ABSTRACT Milling and breadbaking quality of hard-textured wheat may be influenced by alternative alleles at the Wx loci controlling percent amylose in the endosperm, and the puroindoline (pin) loci controlling grain hardness. For this experiment, we developed recombinant inbred lines (RIL) from a cross between Choteau spring wheat cultivar and experimental line MTHW9904. Choteau has the PinB-D1b mutation conferring grain hardness and the Wx-B1a allele at the Wx-B1 locus conferring wild-type amylose content. MTHW9904 has the PinA-D1b allele conferring grain hardness and the Wx-B1b allele conferring lower amylose content, causing a partial waxy phenotype. RIL with the PinB-D1b mutation (n = 49) had significantly softer kernels, higher break flour yield, and higher loaf volume than lines with the PinA-D1b mutation (n = 38). Lines with partial waxy phenotype due to Wx-B1b (n = 43) had significantly lower kernel weight, lower amylose content, and higher flour swelling power than lines with wild-type starch due...

Relationship of Ethanol Yield to Agronomic and Seed Quality Characteristics of Small Grains

ABSTRACT Production of fuel ethanol hinges on the availability of carbohydrate sources, with corn being the crop of choice in most areas. However, in some climatic regions, it is not feasible to grow adequate volumes of corn so other starch sources must be utilized. Here we examined various small grain crops commonly grown in the Northern Great Plains for suitability for ethanol production. Four cultivars each of the hexaploid wheat (Triticum aestivum L.) classes hard red spring (HRS), hard white spring (HWS), soft white spring (SWS), along with durum wheat (Triticum durum L.), and four spring barley (Hordeum vulgare L.) cultivars were grown in replicated plots in two environments in 2006. Agronomic and seed quality traits, along with starch content and ethanol yield over a period of 72 hr were measured on all cultivars. Agronomic yield was highest for the barley cultivars and lowest for HRS and HWS. Seed size was greatest for the durum and barley cultivars. The SWS group had the lowest protein content an...

Hard White Versus Hard Red Wheats: Taste Tests and Milling and Baking Properties

ABSTRACT Molecular markers for the red grain color (R) loci controlling seed color and the polyphenol oxidase (Ppo-A1) locus controlling polyphenol oxidase (PPO) activity in seed have recently been developed. These markers provided the opportunity to convert the hard red spring wheat cultivars Choteau and Hank to white-seeded versions with high and low PPO levels, respectively. These sets of near-isogenic lines provided material to test the effects of seed color and PPO activity on a range of end-use quality traits. We tested recurrent parents Choteau and Hank, along with near-isogenic derivatives with white seed, in two replicated trials in Bozeman, Montana, for end-use quality parameters. The white-seeded lines consisted of both high- and low-PPO near-isogenic lines. The primary impact of white seed was the production of whole wheat bread with a perceived sweeter taste relative to the red-seeded lines. Noodle color was not consistently impacted by the level of PPO variation despite relatively large redu...

Agronomic and Quality Performance of Progeny Lines Derived from Spring Wheat by Durum Wheat Crosses

ABSTRACT Hard red spring wheat (Triticum aestivum L. subsp. aestivum) and durum wheat (Triticum turgidum L. subsp. durum (Desf.) Husn) have both been selected for dryland yield potential and high grain protein, although end uses of flour are different. For this study, 14 tetraploid and 10 hexaploid lines were derived from crosses between tetraploid durum wheat and hexaploid hard red spring wheat. Our objective was to determine the impact of genetic exchange between the two classes on agronomic and quality attributes of derived progeny lines. Yield potential of both the tetraploid and hexaploid progeny was lower than the parental types. Polyphenol oxidase levels were higher by almost twofold in the hexaploid group. The tetraploid progeny group had better noodle color than did the hexaploid group. Bread quality of hexaploid group was superior, with loaf volume 362 cm3 higher than that of tetraploid progeny group. In general, the presence of durum wheat genes in the derived hexaploid lines had little impact ...