Genomic selection strategies in dairy cattle: Strong positive interaction between use of genotypic information and intensive use of young bulls on genetic gain

We tested the following hypotheses: (i) breeding schemes with genomic selection are superior to breeding schemes without genomic selection regarding annual genetic gain of the aggregate genotype (ΔG(AG) ), annual genetic gain of the functional traits and rate of inbreeding per generation (ΔF), (ii) a positive interaction exists between the use of genotypic information and a short generation interval on ΔG(AG) and (iii) the inclusion of an indicator trait in the selection index will only result in a negligible increase in ΔG(AG) if genotypic information about the breeding goal trait is known. We examined four breeding schemes with or without genomic selection and with or without intensive use of young bulls using pseudo-genomic stochastic simulations. The breeding goal consisted of a milk production trait and a functional trait. The two breeding schemes with genomic selection resulted in higher ΔG(AG) , greater contributions of the functional trait to ΔG(AG) and lower ΔF than the two breeding schemes without genomic selection. Thus, the use of genotypic information may lead to more sustainable breeding schemes. In addition, a short generation interval increases the effect of using genotypic information on ΔG(AG) . Hence, a breeding scheme with genomic selection and with intensive use of young bulls (a turbo scheme) seems to offer the greatest potential. The third hypothesis was disproved as inclusion of genomically enhanced breeding values (GEBV) for an indicator trait in the selection index increased ΔG(AG) in the turbo scheme. Moreover, it increased the contribution of the functional trait to ΔG(AG) , and it decreased ΔF. Thus, indicator traits may still be profitable to use even when GEBV for the breeding goal traits are available.     

Energy and nutrient digestibility in NutriDense corn and other cereal grains fed to growing pigs

Two experiments were conducted to measure the energy and nutrient digestibilities in NutriDense corn and other cereal grains. An additional objective was to evaluate the effect of balancing diets with AA on the values measured for DE and ME of corn varieties. In Exp. 1, 6 growing pigs were fitted with a T-cannula in the distal ileum and allotted to a 6 x 6 Latin square design to measure apparent ileal digestibility (AID) and standardized ileal digestibility (SID) values for CP and AA in NutriDense corn, yellow dent corn, barley, wheat, and sorghum. Diets based on each of the 5 cereal grains were formulated, along with a N-free diet. Results of this experiment showed that the AID for most indispensable AA were greater (P < 0.05) in NutriDense corn and wheat than in the other cereal grains. The SID for Lys in NutriDense corn (77.6%) was greater (P < 0.05) than in yellow dent corn (68.5%), and sorghum (56.9%), but not different from wheat (75.1%) and barley (71.7%). The SID for Arg and Met in NutriDense corn also were greater (P < 0.05) than in yellow dent corn (88.1 and 87.2% vs. 84.5 and 82.8%, respectively). For the remaining indispensable AA, no differences in SID between NutriDense corn and yellow dent corn were observed. For all AA, the lowest values (P < 0.05) for AID and SID were obtained for sorghum. If calculated as grams of standardized ileal digestible AA per kilogram of DM, concentrations of all indispensable AA in NutriDense corn were greater (P < 0.05) than in yellow dent corn, but barley and wheat had greater concentrations of most AA than yellow dent corn and NutriDense corn. In Exp. 2, 12 growing barrows were placed in metabolism cages, and the DE and ME of NutriDense corn and yellow dent corn were measured. Both grains were used in diets without or with crystalline AA supplementation. Each diet was fed to 6 pigs in a 2-period, changeover design. The DE and the ME in NutriDense corn (4,004 and 3,922 kcal/kg of DM, respectively) were greater (P < 0.01) than in yellow dent corn (3,878 and 3,799 kcal/kg of DM, respectively). Values for DE and ME were not affected by the addition of crystalline AA to the diets. It is concluded that NutriDense corn has a greater value than yellow dent corn in diet formulations due to increased concentrations of digestible, indispensable AA and energy. However, barley and wheat have greater concentrations, whereas sorghum has lower concentrations, of many digestible AA than NutriDense corn.     

Ash and biochar amendment of coarse sandy soil for growing crops under drought conditions

Appropriate soil amendments may increase plant available water and crop yields on coarse sandy soils under drought conditions. In this study, we applied straw ash or straw biochar from gasification to a Danish coarse sandy subsoil to assess the effects on soil water retention, evapotranspiration and crop yields. Spring barley (2016, 2017) and winter wheat (2018) were grown over three years in columns containing 25cm of organic matter-rich topsoil, 80 cm of amended coarse sandy soil (1.5%, 3%, 6% wt. ash or 1% wt. biochar or control soil) and 45 cm of un-amended subsoil. Precipitation, evaporative demands and soil moisture were recorded across the growth seasons, with 2018 having severe drought conditions. This year evapotranspiration levels increased with increasing ash and biochar content (by 54% and 33% for the 6% ash- and 1% biochar-amended soils, respectively), and plant dry matter increased by 18% in both the 1% biochar- and 6% ash-treated soils compared to the untreated control. A linear relationship was established between in situ field capacity and ash dosage (R² = .96), showing an increase of 2.2% per percentage (wt.) of ash added, while the 1% biochar treatment increased the capacity by 3.5%, indicating a higher efficiency than for ash. However, we did not find significant positive effects on grain yields. The results show that ash and biochar have the potential to significantly increase soil water retention, evapotranspiration and total dry matter yield in drought conditions, but that this may not correspond to an increase in grain yield.     

Development of Nondestructive Screening Methods for Single Kernel Characterization of Wheat

The development of nondestructive screening methods for single seed protein, vitreousness, density, and hardness index has been studied for single kernels of European wheat. A single kernel procedure was applied involving, image analysis, near‐infrared transmittance (NIT) spectroscopy, laboratory density determination, single kernel characterization system (SKCS), and finally Kjeldahl protein determination on the crushed single kernels. Single kernel NIT spectroscopy showed excellent ability to determine protein content, and some ability for determination of single kernel vitreousness. Nondestructive determination of single kernel density, either based on NIT spectroscopy or based on image analysis and kernel weight, needs to be further improved for practical use. The use of SKCS hardness index as a true single kernel hardness reference in a NIT prediction model resulted in a poor predictability. However, by applying an averaging approach, in which single seed replicate measurements are mathematically simulated, a very good NIT prediction model was achieved. This suggests that the single seed NIT spectra contain hardness information, but that a single seed hardness method with higher accuracy is needed to achieve a good NIT prediction model for single kernel hardness.     

Characterization of waxy grain sorghum lines in relation to granule-bound starch synthase

The waxy phenotype, associated with endosperm containing little or no amylose, has been recognized in sorghum (Sorghum bicolor L. Moench) since 1933. Although variants of the waxy gene are well characterized in other cereals, the waxy trait has been assumed to be controlled by a single allele, wx, in sorghum. Recent improvements in technologies encourage re-examination of the waxy sorghums. The objectives of this research were therefore to identify and characterize sorghum lines with differing waxy alleles and to describe the actions of those alleles in crosses. Grain of eight waxy sorghum lines (BTxARG1, BTx630, Tx2907, B.9307, 94C274, 94C278, 94C289, 94C369), three wild-type checks (BWheatland, RTx430, BN122), and F₂ families from crosses among a subset of these lines were evaluated for presence or absence of granule-bound starch synthase (GBSS), the gene product of the wx locus, and wild-type vs. waxy endosperm. The F₂ segregation ratios were tested for fit to a 3:1 ratio using Chi-square analyses. Two distinctly different naturally occurring waxy alleles were identified: One with no GBSS (GBSS−), and one with apparently inactive GBSS present (GBSS+). We propose that the waxy allele with no GBSS be designated wx^a, and that waxy allele with apparently inactive GBSS present be designated wx^b. These two alleles are located in close proximity on the waxy locus. The wx^b allele is dominant to the wx^a allele in terms of GBSS production, and both are recessive to the wild-type Wx in terms of amylose content. The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

Triploid and Hexaploid Regenerants from Hexaploid Timothy (Phleum pratense L.) via Anther Culture

Pollen embryos were obtained from eight genotypes and viable green plants were regenerated from four genotypes in an anther-culture experiment with 165 genotypes of Phleum pratense L. Formation of proembryos inside the cultured anthers during the first 10—12 days was significantly influenced by genotypes and by the type of nutrient media. Primary embryos developed into multiple secondary embryos before regeneration of plants. Among a total of 62 plants regenerated, only 13 were albinos. Of the green regenerants, 11 were triploid while 35 were hexaploid when DNA-content was measured by flow cytometry. Eight plants with a triploid DNA-content did possess the triploid chromosome number of 21. Triploid and hexaploid regenerants from two different parents showed simplified isozyme (GPI and PGD) banding patterns relative to that of their parents.     

Lactoperoxidase-induced protein oxidation in milk

The reaction between lactoperoxidase (LPO) and H(2)O(2) in the presence of bovine serum albumin (BSA), beta-lactoglobulin, or casein was investigated for the formation of protein radicals by freeze-quench electron spin resonance (ESR) and by the formation of the protein oxidation product, dityrosine. The presence of BSA resulted in a dramatic change after 1 min of reaction in the obtained ESR spectrum compared with the spectrum obtained for LPO and H(2)O(2) alone. Furthermore, experiments employing BSA or beta-lactoglobulin resulted in the formation of long-lived protein radicals detectable 10 min after initiation of the reaction. The presence of casein resulted in a minor change in the fine structure of the ESR spectrum after 1 min of reaction compared with LPO and H(2)O(2) alone, but no difference between the two reaction mixtures could be observed after 10 min of reaction. The formation of dityrosine could be detected in reaction mixtures containing LPO and H(2)O(2) after 1 and 10 min of incubation at 25 degrees C both in the absence and in the presence of BSA, beta-lactoglobulin, or casein. The presence of casein resulted in an increased dityrosine concentration compared with the reaction with LPO and H(2)O(2) alone. Endogenous LPO in unpasteurized milk was activated at 25 degrees C by adding 1 mM H(2)O(2). Radical species could be detected directly in the milk by freeze-quench ESR during the initial phase of the reaction, and dityrosine could be measured after 4 h of incubation. The role of LPO activity in the formation of ESR detectable radical species and dityrosine in milk was further verified in ultrahigh temperature (UHT) milk with no endogenous enzyme activity, as the formation of ESR detectable radical species and dityrosine took place in UHT milk only upon the addition of both H(2)O(2) and exogenous LPO.