Dwarfs, semi-lethals and lethals in wheat

The Control of Growth Habit of Marquillo × Kenya Farmer Wheat Dwarf I by Temperature

“…The effects of the 160 temperature on the plants were 2- The reproductive responses to the temperature have been discussed previously (12). In MqlxKF 1, the high minimum leaf number for heading (8)(9)(10) leaves) accounts for its extreme sensitivity, since inactivation of the primary tiller at any earlier stage prevents the heading of the primary tiller. Secondary and tertiary tillers which have lower leaf number requirements j(4) were a-ble to head at a later time.…”

“…The temperature sensitivity of the MqlxKF I hybrids was demonstrated by the chanige from the normal (2), to the "grass-clump" dwarf (2,6,8,9), the late heading "grass-clump" dwarf (6,8) and the "lethal" (6,8,9) morphological forms as the 160 phase of the temperature regime was lengthened.…”

“…Hyrbrids from crosses of many normal wheat varieties exhibit limited leaf elongation, profuse tillering and low fertility under field conditions (3,6,8) and have been termed "grass-clump" dwarfs.…”

The physiological control of F1 grass-dwarfs in Triticum aestivum L.

“…These reports have been reviewed by MCMILLAN (1937) and by MORRISON (1957). The origin of most named varieties carrying factors for the "grass-dwarf" character can be traced to Fife wheats from Canada and other varieties used by FARRER.…”

“…The association of some of the loci responsible for the grass-dwarf phenotype with rust resistance in several varieties (KNOTT and ANDERSON 1956, EVERSON et al 1957, MORRISON 1957and CANVIN and EVANS 1963 has resulted in the transfer of these undesirable loci into varieties in many countries.…”