Characterization of core collection of lentil germplasm for phenology, morphology, seed and straw yields
Increasing and maintaining crop residues in predominantly cereal-based rotations of the US Pacific Northwest is critical to controlling soil erosion. The core collection of lentil (Lens culinaris Medik.) germplasm comprising 287 accessions was evaluated for variation in phenological, morphological and growth parameters including seed yields and residue amounts over a two-year period under conventional tillage and no-till conditions. The objectives of this study were (i) assess lentil genetic variation in germplasm for variation in biomass production and seed yield, (ii) assess the relationship of phenological and morphological traits with biomass and seed yield and (iii) identify high biomass producing germplasm for use as parents in the breeding program. Days to flowering and days to maturity ranged from 31 to 78 and from 71 to 106 days, respectively. Time to flowering in terms of cumulative heat units was a more efficient measurement than days to flowering. Plant height and plant canopy width had a significant association with total biomass, seed yield and residue amounts. Total biomass ranged from 788–6389 kg ha−1 under conventional tillage, while the range under no-till conditions was 1045–6195 kg ha−1. Most of the lines with higher biomass also produced the highest seed yields and residue amounts. Overall, only one accession produced more residue than `Laird'. In the more favorable environment of 1997, six accessions exceeded the control cultivars, `Laird' and `Indianhead', for residue amounts, and seven and twenty-four accessions exceeded control cultivars, `Pardina' and `Brewer', for seed yield. Results indicated that plant height, canopy width at maturity and seed yield explained most of the variation in biomass and residue production. Large seeded germplasm consistently had a longer reproductive growth period than small seeded accessions and had 17%, 7% and 21% more biomass, seed yield and residue, respectively. Our data indicated significant variation in lentil germplasm for biomass, seed yield and residue amounts to warrant their use in the breeding program.
Breeding has selected for architectural and photosynthetic traits in lentils
Genetic progress in seed yield in lentils (Lens culinaris Medik) has increased by 1.1% per year in Australia over the past 27 years. Knowing which plant traits have changed through breeding during this time can give important insights as to how lentil yield has increased. This study aims to identify morphological and physiological traits that were directly or indirectly selected between 1993 and 2020 in the Australian lentil breeding program using 2 years of experimental data. Major changes occurred in plant architecture during this period. Divergent selection has seen the release of varieties that have sprawling to very upright types of canopies. Despite this genetic diversity in recently released varieties, there is an overall tendency of recently released varieties having increased plant height and leaf size with reduced number of branches. Increased light interception was positively correlated with year of release (YOR) and yield, and likely results from indirect selection of yield and taller plant types. There is an indication that recently released varieties have lower CO2 assimilation rate, stomatal conductance and canopy temperature depression (CTD) at high ambient temperatures (~30°C). Understanding lentil physiology will assist in identifying traits to increase yield in a changing climate with extreme weather events.
The infection process, sporulation and survival of Alternaria helianthi on sunflower
SUMMARY 
 
Electron microscopy was used to study the infection of sunflower leaves by Alternaria helianthi. Conidia germinated by producing one to many germ tubes which grew across the leaf surface before forming appressoria. The fungus directly penetrated its host through the cuticle and epidermis. Entry into the host through wounds and stomates was also observed. Extracellular sheaths were found to be associated with germ tubes and intercellular hyphae of A. helianthi. Conidiophores developed through collapsed stomates, from leaf veins, trichomes and also from mycelium growing across the host leaf surface. Microcylic conidia were produced directly from parent conidia under certain conditions. Studies using a volumetric spore trap showed that the airborne spore concentration followed a distinct periodicity with peaks occurring between 0900 and 1100 h each day. Laboratory studies showed that safflower, noogoora burr and bathurst burr could serve as alternative hosts for A. helianthi. The pathogen was readily isolated from sunflower crop debris from a diseased crop that had been harvested 1 yr earlier.