Inheritance of Reaction to Stem Rust in Crosses of Timstein with Thatcher, Newthatch, and Mida¹

The genetic basis for low coefficient of infection to stem rust in common wheat

“…W3300 originated from the cross (Frontana x Kenya 58 x Newthatch) x Thatcher, and of these, Thatcher and Newthatch are both known to possess Sr5 (HAYES et al ., 1936 ;Koo and AUSEMUS, 1951) . Sr9b must have been contributed by Frontana, which carries this gene (KNOTT and SHEN, 1961) .…”

The Genetics and Expression of Resistance in Plants to Rusts of the Genus Puccinia

“…Usually plants become more resistant as they get older. This "maturative" or "adult plant" resistance is of extreme practical importance in cereals, maize, and other crops (1,18,19,24,33,35,41,43,53,58,87,101). Some forms supersede seedling susceptibility and appear to be a generalized type of resistance.…”

“…For rust resistance, complementary action of two recessive genes (7,43,53,67,77), three recessive genes (8,57), two domi nant genes (2,51,67,68,91,95), and of one dominant and one recessive gene (95) are known. Since complementary gene action implies that there is an interaction between the products of two or more genes, this kind of resistance, in the light of the gene-for-gene theory, might be more stable than resistance caused by a single gene or by several genes each functioning individually to condition resistance.…”

“…The modifica tion is complete. Genes that condition a higher level of rust resistance are commonly epistatic to those conditioning a less resistant reaction (10,34,53,91). The expression of a gene for rust resistance may be inhibited by a gene at another locus (7,61,67,77,94).…”

Isolation of complementary genes conditioning crown rust resistance in the oat variety Bond

“…For example the bread wheat variety Timstein in crosses with Chinese Spring appeared to possess two complementary dominant linked genes on chromosome 6B (X) conditioning resistance to stem rust (SEARS and RODENH1SER, 1948). Koo and AUSEMUS (1951) found only one gene responsible for resistance in Timstein in crosses between it and certain other varieties; it was assumed that the latter carried one of the complementary resistance genes. However, LUIG (1960) and SEARS and LOEGERING (1961) claimed that F~ ratios observed in crosses between Timstein and Chinese Spring were due to aberrant single gene segregation.…”