N. McLean

Regenerative trait and cold hardiness in highly productive cultivars of alfalfa and red clover

SummaryIn earlier work on improvement of persistance in forage legumes, we selected genotypes from highly productive cultivars of alfalfa, Algonquin and Apica (Euphytica 45: 105–112, 1990) and cv. Florex red clover (Plant Cell Reports 8: 395–398, 1989) capable of in vitro regeneration from callus and cell culture. The alfalfa germplasm and its F1 progeny as well as an F2 red clover population were tested for cold stress tolerance. Plantlets were hardened in culture tubes at 2 or 5°C, 8h photoperiod, for at least four weeks and then subjected to freezing temperatures, −16 or −10°C for alfalfa and red clover, respectively. Survival of regenerative genotypes was significantly higher than of the non-regenerative ones in both species. A strong oositive correlation (r=0.78) between the regenerative trait and plant survival was found in alfalfa. The experiments indicate that in vitro selection for regenerative trait may improve cold stress tolerance of alfalfa and red clover.

Inheritance of somatic embryogenesis in red clover (Trifolium pratense L.)

Abstract Red clover genotypes capable of regenerating plantlets in vitro from non-meristematic tissue-derived callus are rare. Selection for genotypes capable of somatic embryogenesis identified a clone comprised of a group of plantlets regenerated from a hypocotyl-derived callus culture on L2-based media and another group of plantlets originating from crown divisions of the epicotyl-derived plant. The callus-derived plants of this clone were highly regenerative when reintroduced to callus culture, but the epicotyl-derived plants produced nonregenerative callus cultures. F1, F2 and BC1 populations were evaluated to determine the mode of inheritance of the regeneration trait. Reciprocal crosses did not differ, indicating a lack of maternal effects. Results were compatible with genetic control of regeneration by two complementary genes. We propose the genotype Rn1-Rn2- for regenerative plants. Three petiole segment explants were sufficient to evaluate regenerative ability in seedlings. Regenerative ability was often associated with abnormal leaf morphology in a few to several leaves.

Enhanced expression of a cold-induced gene coding for a glycine-rich protein in regenerative somaclonal variants of red clover (Trifolium pratense L.)

Cold hardiness and in vitro regeneration are closely related traits in selected alfalfa and red clover germplasms. We investigated the cold-induction of three genes, MsaCIA, MsaCIB and MsaCIC, implicated in the cold tolerance of alfalfa, in non-regenerative and regenerative somaclonal variants of red clover by Northern blot analysis using alfalfa cDNA clones as hybridization probes. Only the MsaCIA gene exhibited increased steady-state mRNA levels in cold-acclimated red clover. We observed, however, enhanced-cold induction of steady-state levels of MsaCIA gene transcripts in all regenerative somaclonal variants compared to non-regenerative red clover lines. Moreover, these two traits, regeneration and enhanced cold-induction of MsaCIA, were concomitantly transmitted to progeny suggesting that enhanced expression of MsaCIA and the regenerative trait are either linked, or the expression of both traits are regulated by a ‘master’ gene whose expression is modified by somatic embryogenesis.

In vitro selection for improved seedling vigour in birdsfoot trefoil (Lotus corniculatus L.)

Establishment of productive stands of birdsfoot trefoil (Lotus corniculatus L.) is often difficult due to poor seedling vigour. Objectives of this study were to evaluate the relative effectiveness of in vitro selection conditions for seedling vigour and to choose the best lines for further evaluation. Birdsfoot trefoil seedlings from cvs. Leo and Upstart were selected on the basis of in vitro rate of germination at 5, 12 and 20 °C and subsequent seedling growth at 20 °C. Two cycles of recurrent selection were carried out. Progeny from both cycles of selection were evaluated under controlled and field conditions. In general, selection temperatures did not significantly affect emergence, individual shoot dry matter production or total shoot dry matter production. Emergence and total shoot dry matter yield were higher for selections within cv. Upstart than for selections within cv. Leo. Seedling vigour of cycle-2 selections was not superior to cycle-1 selections. Failure to make gains during the second cycle...

Development of quality assurance protocols to prevent GM-contamination of organic crops

Publisher Summary Genetic engineering holds much promise for farmers, consumers, and the biotechnology industry, but the exploitation of GM crops would require responsible introduction which, in turn, requires the creation of effective and acceptable transgene confinement protocols. These protocols must be based on knowledge of the nature and interaction of those factors that contribute to transgene movement and a realistic consideration of the cooperation required to make confinement effective. The protocols must also be based on the understanding that the movement of transgenes beyond their intended destinations under current agri-food production and handling systems is a certainty and, that once transgenes have escaped into the environment, it is unlikely that they can be absolutely retracted. In order to be administered effectively, the protocols must include the assignment of responsibilities for transgene confinement, which are enforced through law.

Fumigating broiler hatching eggs with lysozyme product (Inovapure) to reduce eggshell microbial load

ABSTRACT Experiments were conducted to evaluate the effectiveness of a lysozyme product (InovapureTM) (LP) against E. coli penetrating eggshells. In the first microbiological experiment, 60 agar‐filled eggs were inoculated with E. coli suspension, then fumigated with distilled water, 1.5% or 3.0% LP or a quaternary ammonium product (QA) at 0.125% for 10 min. In the second microbiological experiment, another 60 agar‐filled eggs were fumigated with the same sanitizer treatments first, then inoculated with the E. coli suspension. Eggshells were candled and visual colonies were counted after 48 h incubation. An animal experiment was conducted to evaluate LP applied to the surface of 2080 broiler hatching eggs on hatching and growth performance. Hatching eggs were submerged in an E. coli suspension. After drip drying, eggs were randomly divided into four fumigation treatments, each with four subsets of 150 eggs. Fumigation treatments were the same as in the microbiological experiments. Eggs were incubated in 8 incubators (2 replicate incubators per treatment) and the broilers were grown to 33 d of age. In the microbiological experiments, inoculated eggs fumigated with 3.0% LP and 0.125% QA reduced (P < 0.05) the total amount of E. coli to 11 cfu/egg and 10 cfu/egg, respectively. When eggs were sanitized prior to inoculation, 3.0% LP demonstrated (P < 0.05) ongoing bactericidal action to prevent E. coli penetration. No differences in hatchability, fertility rate or egg weight loss percent were found among sanitation treatments. At hatch, body weight or the ratio of yolk sac weight to yolk‐free body weight were not affected by the sanitation treatments. However, the application of sanitizers decreased (P < 0.05) the presence of E. coli in the yolk sac of newly hatched chicks. Feed consumption, body weight and feed conversion ratio were not affected by sanitation treatments. However, average daily body weight gain was lower (P < 0.05) following QA. Overall, 3.0% LP demonstrated acceptable activity against E. coli on eggshells, and provided ongoing bactericidal action to prevent E. coli penetration without negatively affecting growth performance.

Meal residual oil level and heat treatment after oil extraction affects the nutritive value of expeller-pressed canola meal for broiler chickens

Abstract: This experiment determined the effects of expeller-pressed canola meal (EPCM) residual oil (10% vs. 14%) and heat treatment at 115 °C for 25 min on the nitrogen-corrected apparent metabolizable energy (AMEn) value and amino acid (AA) digestibility for broilers. Day-old male chicks (six per cage) were fed six test diets (five cages per diet) from 14 to 21 d using the substitution method in a 2 × 2 factorial design. Increasing EPCM oil content from 10% to 14% increased (P < 0.05) EPCM AMEn value by 287 kcal kg-1. There was heat treatment by oil level interaction (P < 0.05) on standardized ileal digestibility of arginine, isoleucine, leucine, lysine, phenylalanine, threonine, and valine for EPCM in which heat treatment of the low oil EPCM reduced (P ≤ 0.0012) the digestibility of all these AA, but heat treatment of the high oil EPCM only reduced lysine digestibility. In conclusion, heat treatment of EPCM reduced its AMEn value and digestibility of some AA. The AA digestibility of EPCM with low oil was reduced more by heat treatment than EPCM with high oil content, implying that the negative effects of heat treatment on AA digestibility increases with a decrease in residual oil content in EPCM.

Evaluating Brassica napus and Brassica juncea meals with supplemental enzymes for use in laying hen diets: production performance and egg quality factors

Abstract Juncea meal (JM) has higher crude protein and energy and less fibre compared with canola meal (CM) potentially making it more suited for inclusion in laying hen diets. The objective of this study was to compare the inclusion of JM to CM and soybean meal (SBM) in diets of white-shell egg laying hens on production performance and egg quality characteristics. Ten diets were fed to 360 Lohmann LSL-Lite laying hens over four feeding phases during the 48 wk trial. Diets consisted of a SBM control, 10% or 20% CM (CM-10 or CM-20), and 10% or 20% JM (JM-10 or JM-20) with or without a phytase and multicarbohydrase enzyme cocktail. Juncea meal-20 (JM-20) reduced body weight (P > 0.05) compared with SBM by 122 g hen-1 but was not different from CM. Feed consumption, egg production, feed efficiency, and mortality were unaffected by meal or enzyme inclusion (P > 0.05). Feeding CM or JM did not result in any commercially important changes to egg quality, and enzyme inclusion had no effect. Up to 20% CM and JM could be included in laying hen diets without detrimental effects on production performance and egg quality characteristics. Enzyme inclusion did not improve performance of meal types.