Kenneth F. Grafton

A major QTL for common bacterial blight resistance derives from the common bean great northern landrace cultivar Montana No. 5

Knowledge of the evolutionary origin and sources of pest resistance genes will facilitate gene deployment and development of crop cultivars with durable resistance. Our objective was to determine the source of common bacterial blight (CBB) resistance in the common bean Great Northern Nebraska #1 (GN#1) and GN#1 Selection 27 (GN#1 Sel 27). Several great northern cultivars including GN#1, GN#1 Sel 27, and Montana No.5 (the female parent of the common x tepary bean interspecific population from which GN #1 and GN # 1 Sel 27 were derived) and known susceptible checks were evaluated for CBB reaction in field and greenhouse environments. These genotypes and CBB resistant and susceptible tepary bean including Tepary #4, the male parent and presumed contributor of CBB resistance toGN#1 and GN#1 Sel 27, were assayed for presence or absence of three SCAR markers tightly linked with independent QTLs conditioning CBB resistance. The parents and F2 of Montana No. 5/GN #1 Sel 27 and Montana No.5/Othello(CBB susceptible) were screened for CBB reaction and SCAR markers. CBB resistance in Montana No.5 was comparable to that of GN#1 and GN#1 Sel27. The SAP6 SCAR marker present in GN#1 and GN#1 Sel 27 was also present in Montana No.5, and it co-segregated (R2 =35%) with the CBB resistance in the Montana No.5/Othello F2 population. Although a few CBB resistant and susceptible transgressive segregants were found in the F2 of MontanaNo.5/GN #1 Sel 27 and later confirmed by F3 progeny tests, SAP6 SCAR marker was present in all progenies. None of the tepary bean specific CBB resistance-linked SCAR markers were present in GN#1, GN#1 Sel 27, or Montana No.5. A cluster analysis of 169 polymorphic PCR-based markers across three common bean and Tepary #4 indicated that GN#1, GN#1 Sel 27, and Montana No.5 were closely related, and not related at all with Tepary #4.Thus, these results clearly indicate Montana No.5, not Tepary #4, as the source of CBB resistance in GN#1 and GN#1 Sel 27.

Genetic diversity and mineral composition of common bean seed

Concentrations of nine elements essential for human nutrition were studied in seed of eight dry bean (Phaseolus vulgaris L) cultivars grown at five field locations. The cultivars (two Navy, one Great Northern, one Pinto, one Pink, one Cranberry and two Red Kidney) varied in seed weight from 167 to 560 mg per seed. Seed Ca (r  = −0.78, P < 0.001), Mn (r  = −0.67, P < 0.001) and Mg (r  = −0.45, P < 0.001) were negatively related to seed weight. In contrast, seed P (r  = 0.44, P < 0.001) increased with increasing seed weight. Concentrations of N, K, Fe, Zn and B were poorly related to seed weight but differed among cultivars. The two Navy bean cultivars, Voyager and Norstar, differed in concentrations of seed Ca and Fe. Voyager seed contained a mean of 49% more Ca and 19% more Fe than Norstar seed. Voyager also contained a mean of 67% more Ca than that reported for Navy bean in the USDA Nutrient Database. Genetic variability in bean seed may be utilised to increase the mineral content of common bean. © 2001 Society of Chemical Industry

Accumulation of Calcium in Bean Cultivars Differing in Seed Size

Accumulation of Ca, Mg and K, the principal cations in dry bean (Phaseolus vulgaris L) seed, was studied under field and greenhouse conditions. ‘Cran-09’, a cranberry bean and ‘Norstar’, a navy bean, were grown to maturity under greenhouse conditions. ‘Cran-09’ had a seed weight of 605 mg, a seed Ca concentration of 1·2 g kg-1 and a Ca harvest index of 0·032. The corresponding three parameters in ‘Norstar’ were a seed weight of 161 mg, a seed Ca concentration of 2·2 g kg-1 and a Ca harvest index of 0·064. The difference in seed Ca concentration was not due to increased absorption of Ca by ‘Norstar’, but rather was due to a larger proportion of Ca in plant tops being diverted to the seed component. The larger seed Ca concentration in ‘Norstar’ was compensated to some extent by a smaller seed K concentration. In contrast to Ca, cultivar had relatively little effect on harvest indices for Mg, K, N and P. The average seed Ca concentration in six navy bean cultivars grown under field conditions was 90% more than that of three kidney and three cranberry bean cultivars.

Distribution of selected elements between the seed coat and embryo of two black bean cultivars

Differences in distribution of minerals between the seed coat and embryo of plant seed can affect their bioavailability. Concentrations of iron [Fe], manganese [Mn], zinc [Zn], calcium [Ca], magnesium [Mg], potassium [K], and phosphorus [P] in these seed fractions of two black bean (Phaseolus vulgaris L.) cultivars (T39 and UI-911) were studied in field experiments conducted on acid and calcareous soils. Seed of T39 and UI-911 at the acid soil site had 34% and 45% higher [Fe], respectively, than at the calcareous soil site. Seed-coat [Fe] in UI-911 was substantially higher than that in T39. In contrast, embryo [Fe] was higher in T39 than UI-911. Mean percentages of the total seed Fe located in the seed coat were 33% and 32% for UI-911 at the acid and calcareous soil sites, respectively. The corresponding percentages for T39 were 14% and 18%, respectively. Although UI-911 accumulated higher percentages of Ca, Mg, and Zn in the seed coat than T39, the cultivar differences were relatively small. Mean percentages of dry matter and elements in the seed, averaged over cultivars and sites, found in the seed-coat fraction were: Dry matter=10%, Ca=84%, Fe=24%, Mg=18%, K=8%, Zn=7%, Mn=3%, and P=2%. There is apparently a genetically-controlled barrier to the movement of Fe between the seed coat and embryo during seed development in P. vulgaris.

Plant Zinc and the Zinc‐Efficiency Trait in Navy Bean

Abstract Seed of zinc (Zn)‐efficient and Zn‐inefficient navy bean (Phaseolus vulgaris L.) genotypes differ in Zn concentration [Zn]. Greenhouse studies were conducted to determine how Zn and P fertilizers influence seed [Zn] and within‐plant distribution of Zn in the navy bean genotypes Voyager (Zn‐efficient) and Albion (Zn‐inefficient). Addition of 60 and 120 mg P kg−1 in the absence of added Zn to a Calciaquoll low in available P and Zn decreased seed yields of Albion by 18 and 59%, respectively, but increased seed yields of Voyager by 32 and 41%, respectively. However, addition of fertilizer P with 4 mg Zn kg−1 increased seed yields of both genotypes. Seed [Zn] was generally higher in Voyager than in Albion, was increased by Zn fertilizer, and decreased by P fertilizer. In a follow‐up experiment seed [Zn] of Voyager and Albion converged as fertilizer Zn was increased from 8 to 64 mg kg−1. In contrast to seed [Zn], leaf, stem and pod‐wall [Zn] of Albion at maturity were higher than those of Voyager at elevated levels of fertilizer Zn. This crossover pattern for maternal‐plant [Zn] at maturity also occurred in shoots of 18‐d‐old plants. Differences in seed [Zn] between the two genotypes were generally most pronounced when Albion contained greater than 20 and less than 35 mg kg−1 of seed [Zn]. Seed [Zn] is superior to leaf and stem [Zn] for selection of Zn‐efficient navy bean genotypes in plant breeding research.