PCR assays were used to identify Colletotrichum acutatum and C. gloeosporioides out of 14 fungal cultures obtained from seed samples of selected yellow and Andean lupin cultivars. The results allowed for a classification of all fungal cultures to C. acutatum. No C. gloeosporioides culture was identified. In addition, the comparison of rDNA sequence fragment from one of the cultures tested with sequences available in the NCBI/GeneBank database confirmed that the species identified was C. acutatum. The BIO-PCR technique was also used to detect potential inoculum of both species in two lupin seed samples. The results of BIO-PCR assays showed that two lupin seed samples were infected with C. acutatum while no isolate of C. gloeosporioides was detected.
Seeds of the Andean lupine are characterised by high nutritional value, and the plant could become an important crop in the production of food and forage. This legume continues to attract growing interest around the world. A field experiment was carried out in in Lower Silesia, Poland, in 2011-2012. Two Andean lupine morphotypes (indeterminate and determinate) were analysed. Andean lupine was grown in treatments characterised by different sowing dates and plant density per m2. Seed yield, macronutrient content, protein content and health were evaluated at harvest. Seed yield was determined by the interaction of all experimental factors. The indeterminate form produced a significantly higher yield than the determinate form, regardless of the sowing date. The factors had little influence on the mineral content of seeds and total protein content. Andean lupine seeds were colonised mostly by saprotrophic fungi of the genera Alternaria, Cladosporium, Epicoccum and Rhizopus and pathogenic fungi of the genera Botrytis, Colletotrichum and Fusarium. Delayed sowing contributed to seed colonisation by fungi of the genus Colletotrichum. The determinate form was more susceptible to infection than the indeterminate form. Molecular analysis showed that the Colletotrichum isolates found in the study belong to the Colletotrichum acutatum species complex. The pathogen causing lupine anthracnose, isolated from the seeds of Andean lupine in the present study, was identified as Colletotrichum lupini (within C. acutatum complex) in a molecular analysis, and its DNA sequence was compared with those of the isolates deposited in the GenBank.
The pollen grain germination and the growth of pollen tubes after intra- and interspecific reciprocal pollination of Lupinus albus L., L. mutabilis Sweet, and L. angustifolius L. were examined. Results of microscopic observations of pollen grain germination and pollen tube growth enable to deny the existence of certain barriers that prevent fertilization after pollination of L. albus flowers with pollen of L. angustifolius and vice versa, as well as after pollination of L. mutabilis flowers with pollen of L. angustifolius and vice versa. Some delay in pollen grain germination and a slower growth of pollen tubes were observed in all combinations, as related to intraspecific ones, though in the case of each interspecific combination pollen tubes reached the ovary. Moreover, a different level of pollination efficiency (the number of growing pollen tubes) and various rates of pollen grain germination and pollen tube growth, depending on the direction of pollination, were found. The noted pollination efficiency may generally be considered to be low.