* Supported by USDA-CSU Cooperative Research Project No. 58-9AHZ-2-265 and CSU Hatch project.

** Crop Research Division, DSIR, Private Bag, Christchurch, New Zealand

Chromosome numbers of plants in the progenies of triploid plant of cultivar Golden Promise derived from callus were studied. The chromosome numbers were listed in Table 1.

All plants from these seeds were transplanted into clay pots in the greenhouse. Two plants (one with 2n = 19, another 2n = 17) died at early seedling stage. Diploid plants (2n=14) grew most vigorously. Simple trisomic plants (2n=15) had less vigor than diploid plants but grew more vigorously than rest of the plants which had high chromosome numbers. The plants with chromosome number 16, 17, 20, and 25 were weak with shorter culm and smaller plant organs.

Among eleven simple trisomic plants, five different morphological types were recognized; they were tentatively identified as Bush (Triplo 1), Pale (Triplo 3), Robust (Triplo 4), Purple (Triplo 6) and Semi-erect (Triplo 7). Further cytogenetic studies will be conducted to confirm the types of these trisomics.

Four plants could not head which included two plants with 2n=17, one plant with 2n=16 and another with 2n=20. Most of the plants headed normally. Diploid plants had earliest heading, followed by simple trisomic plants about a week later. Plants with high chromosome numbers headed three weeks later than diploid plants. However, the Bush type trisomics (Triplo 1) were too weak to head at the same time as the other simple trisomics and headed 10 days later than other simple trisomics.