Many Himalayan wheats were introduced from Nepal by Nakao, a member of The Japanese Himalayan Expedition to Nepal, 1952-53. The introduced wheats are classified into 17 different botanical varieties, all of which belong to Triticum vulgare. Most of them belong to Indian wheat group and some belong to Tibetan wheat group. The grain quality of most of the Nepalese wheats,is hard flinty. The low Himalayan hills are considered to be the home of the flinty bread wheats in the world. Namely three stocks from there such as Hard Red Culcutta, Cenun and Etwah furnished very important materials for the breeding of the world famous leading wheat varieties as Marquis, Ruby, Prelude, Garnet and Reward in Canada and U.S.A. and Federation and Aurora in Australia.
X-Ray Induced Mutations in Einkorn Wheats
Many characters of common wheats, including some of economic importance, have been genetically studied, but very few linkages have been found. The difficulties are due mainly to their polyploid constitution. However, Einkorn wheats which are diploid with seven pairs of chromosomes are fairly well adapted to genetic and cytological studies. By means of induced mutations and induced chromosomal rearrangements, including reciprocal translocations, the genetic and cytological analyses have been largely developed.
Various types of induced reciprocal translocations in Triticum aegilopoides and T.monococcum were analyzed, and a series of 6 types involving 7 chromosomes of Einkorn wheat from a to g were established. They are a-b, b-c, c-d, d-e, e-f and e-g. Subsequently, by the successive crosses, plants with all the possible combinations of rings and pairs have been obtained.
These materials were also used for locating genes in respective chromosomes. Accordingly, the seven linkage groups have been established.
d-chromosome with lethal-1 and f-chromosome with lethal-2 have been combined in a ring of six chromosomes, as
, where chromosomes
with lethal genes are given with bcld face.The permanent heterozygosity should be maintained by this plant due to the balanced lethal mechanism known in Oenothera.
Right- and Left-handedness
Right- and left-handed leaves are defined according to the way of folding: i.e. when the overlapping edge of a leaf is on the right hand of the observer, it is called right-handed and if on the left hand, left-handed. The right- and left-handedness of a spikelet has been defined from the position of its first floret, namely, when the first floret is on the right, seen from dorsal side, a spikelet is right-handed, and when it is on the left, left-handed. Generally, the right-handed and left-handed leaves are regulary arranged in alternative sequence from the base up to the flag leaf. This regularity is continuously found in the spikes.
The data of observations on the right- and left-handedness of the leaves and spikelets from the first foliage leaf to the apical spikelet, indicated that the degree of the intensity of the regularity changes throughout the developmental stage. Namely the regularity appears from the 3rd or 4th leaf's position and is maintained up to around the 10th spikelet, but it disappears again around 20th spikelet.
Concordance proportion: Two kinds of the measure of the intensity of the regularity are used. One is the concordance proportion (Ck), which represents the intensity of regularity at the kth position on the stem, and the other is the mean concordance proportion (C) which expresses the intensity of the polarity of investigated shoots or plants. They can be obtained by the following formulas:
