Browsing by Author "Weeden, Norman F."

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Canola and Sweet Lupin -- Potential New Rotation Crops for Central Montana (2003)
(Central Agricultural Research Center, 2003) Chen, Chengci; Wichman, David M.; Neill, Karnes E.; Brown, Jack; Weeden, Norman F.; Vavrovsky, Joe
This paper evaluates new regular and specialty canola genotypes from public and private breeders from various regions of U.S. and Canada for adaptation and evaluates narrow leaf lupine genotypes, from Australia and Poland, for adaptation and yield potential in central Montana. Due to the severe summer drought in 2003, canola and lupin did not perform well in the field. Yields were extremely low. Although differences were observed among the cultivars, there was not enough evidence to justify the adaptability of the genotypes in this one-year trial under an unusual weather pattern. The growth chamber study shows great variations among canola genotypes in base temperature and heat unit required for emergence. These results will provide a reference for the selection of canola genotypes for early planting. Previous studies have shown yield advantage of early seeding.
Domestication of Pea (Pisum sativum L.): The Case of the Abyssinian Pea
(2018-04) Weeden, Norman F.
Phylogenetic relationships of the Abyssinian pea (Pisum sativum ssp. abyssinicum) to other subspecies and species in the genus were investigated to test between different hypotheses regarding its origin and domestication. An extensive sample of the Pisum sativum ssp. sativum germplasm was investigated, including groups a-1, a-2, b, c, and d as identified by Kwon et al. (2012). A broad sample of P. fulvum but relatively few P. s. ssp. elatius accessions were analyzed. Partial sequences of 18 genes were compared and these results combined with comparisons of additional genes done by others and available in the literature. In total, 54 genes or gene fragment sequences were involved in the study. The observed affinities between alleles in P. ssp. sativum, P. s. ssp. abyssinicum, P. s. ssp. elatius, and P. fulvum clearly demonstrated a close relationship among the three P. sativum subspecies and rejected the hypothesis that the Abyssinian pea was formed by hybridization between one of the P. sativum subspecies and P. fulvum. If hybridization were involved in the generation of the Abyssinian pea, it must have been between P. s. ssp. sativum and P. s. ssp. elatius, although the Abyssinian pea possesses a considerable number of highly unique alleles, implying that the actual P. s. ssp. elatius germplasm involved in such a hybridization has yet to be tested or that the hybridization occurred much longer ago than the postulated 4000 years bp. Analysis of the P. s. ssp. abyssinicum alleles in genomic regions thought to contain genes critical for domestication indicated that the indehiscent pod trait was independently developed in the Abyssinian pea, whereas the loss of seed dormancy was either derived from P. s. ssp. sativum or at least partially developed before the P. s. ssp. abyssinicum lineage diverged from that leading to P. s. ssp. sativum.
Proanthocyanidins: Key for Resistance to Globisporangium (Formerly Pythium) Seed Rot of Pea
(American Society for Horticultural Science, 2024-01) Ewing, Elmer E.; Weeden, Norman F.; Simko, Ivan
Pea (Pisum sativum) dominant for the fundamental color gene A showed a high level of resistance to Globisporangium ultimum (formerly Pythium ultimum) seed rot. Reciprocal crosses demonstrated that, with our materials, such resistance was associated with the testa (seedcoat) phenotype but not the embryo phenotype. Dominance of A over a was complete for this trait. Neither wrinkled seed form (r) nor green cotyledons (i) diminished resistance when A was dominant, although both recessive alleles diminished resistance when seeds were borne on white-flowering (a) plants. The product of the A gene functions in the pathway leading to flavonoids, including proanthocyanidins (PAs) and anthocyanidins. We found that resistance to G. ultimum seed rot was closely associated with not only dominant A but also testa PAs and testa sclerenchyma. Even A testas that lacked anthocyanins but contained PAs and sclerenchyma showed a high level of seed rot resistance. Moreover, a mutation removing PAs and sclerenchyma in a narrow zone from the hilum to the radicle markedly increased susceptibility. The PAs in pea testas were predominantly prodelphinidins in seeds from purple-flowered plants (A B) and procyanidins from pink-flowered plants (A b). Compared with procyanidins, prodelphinidins have higher antioxidant activity but are more likely to sequester iron, a particular concern with dry pea. Although A B testas were more resistant than A b to seed rot, the difference seemed too slight to militate against growing pink-flowered pea. We stressed the need for more histological comparisons of A B and A b testas, and we indicated that genes and their phenotypic effects examined during the current study could be useful for modeling biosynthesis of PAs and related cell walls.