Transferring Resistance to Colletorichum truncatum from Wild Lentil Species to Cultivated Lentil Species (Lens culinaris subsp. culinaris)
Date
2006-06
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ORCID
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Masters
Abstract
Lentil, Lens culinaris subsp. culinaris Medic. is an important legume crop on the Canadian prairies. Fungal diseases account for the majority of biotic stresses reported on lentil. Anthracnose, caused by Colletotrichum truncatum (Schwein.) Andrus and W.D. Moore, is a major barrier to yield and quality in lentil. Pathogenicity testing has revealed two races of C. truncatum in western Canada. There are no cultivars or landraces identified with race Ct0 resistance in the literature. It has been reported that wild lentil species, Lens ervoides (Brign.) Grande and L. lamottei Czefr., have shown resistance to race Ct1 and race Ct0 in field and greenhouse experiments. The main objective of this research was to develop interspecific hybrids between L. culinaris subsp. culinaris and wild lentil species, and to subsequently evaluate the transfer of race Ct0 resistance into cultivated lentil background. Cultivated lentil cultivar Eston was crossed in all possible combinations, including reciprocals, with six L. ervoides accessions (IG 116014, IG 72569, IG 72564, IG 72653, IG 72654 and L-01-827A). Cultivated lentil breeding line 971-16 was crossed with five L. lamottei accessions (IG 110810, IG 110811, IG 110813, IG 110812 and IG 72552) in all possible cross combinations, including reciprocals. Embryo rescue was used to facilitate the recovery of interspecific hybrid embryos. Two interspecific populations (LR-59 and LR-61) were developed and evaluated for resistance to anthracnose races.
Population LR-59 derived from the cross L. culinaris subsp. culinaris cv. `Eston' x L. ervoides L-01-827(A) showed resistance to both anthracnose races.
Chi-square tests of goodness-of-fit to one and two gene ratios at F7:8 RILs indicated that resistance to race Ct1 and race Ct0 may be conferred by two recessive genes. Correlation analysis of disease scores between generations showed no significant relationship; however, there was a highly significant correlation between F7:8 disease scores for both anthracnose races.
Only four lines of Population LR-61derrived from the cross L. culinaris subsp. culinaris 971-16 x L .lamottei 110811 were advanced to the F4:5 generation due to poor seed germination and seedling development. Evaluation of the four lines showed that resistance to both race Ctl and race Ct0 was transferred to the cultivated lentil; however, genetic control could not be determined.
lntraspecific crosses of L. lamottei were made to determine the genetic control of anthracnose resistance. Progeny of two successful crosses did not show resistance to race Ct 1 or race Ct0.
An efficient in vitro protocol for propagation of lentil and interspecific hybrids was developed. The largest effects on shoot number and length, and root number length of roots were due to species differences and the use of activated charcoal-supplemented medium.
Cytological and fertility studies on Population LR-61 showed extra chromosomal pieces and bridge formation during meiosis, contributing to reduced fertility in the interspecific hybrid plants. There were few viable pollen grains and reduced number of pollen grains in interspecific hybrid plants, indicating reduced pollen production and viability.
In situ hybridization studies were not successful in locating chromosome introgressions from wild lentil species into interspecific hybrid of Population LR-61. RAPD studies of the parental genotypes and interspecific hybrids of Population LR-61 showed the presence of an extra polymorphic band on L. lamottei genotype IG 110811. This band was transmitted to an F2 hybrid line.
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Degree
Master of Science (M.Sc.)
Department
Plant Sciences
Program
Plant Sciences