Yoshida - 1981 - Fundamentals of Rice Crop Science

78 FUNDAMENTALS OF RICE CROP SCIENCE
Table 2.6. Cold water tolerance of United States rice varieties. a
Crop
intro- Length, Survival,
Variety duction Location Grain Maturity % of % of
no. type group b Caloro Caloro
Caloro 1561-1 California Short Midseason 100.0 100.0
Calady 40 9202 California Medium Midseason 109.6 91.2
Mochi Gomi 9051 California Glutinous Midseason 96.6 88.2
Calrose 8988 California Medium Midseason 91.1 95.5
Colusa 1600 California Short Early 89.1 64.6
Arkrose 8310 Arkansas Medium Midseason 88.9 91.2
Cody 8642 Ark. & Mo. Short Early 78.2 100.0
Fortuna d 1334 Southern Long Midseason 73.7 c 79.4
Early Prolific d 5883 Southern Medium Early 72.4 c 90.0
Rexoro 1779 La., & Texas Long Late 67.4 c 91.2
Lacrosse 8985 Southern Medium Early 65.7 c 86.7
Nato 8998 Southern Medium Early 65.7 c 82.4
Century Patna 231 8993 Southern Long Early 61.2 c 73.5
Texas Patna 8321 La., & Texas Long Late 60.0 c 85.3
Gulfrose 9416 Southern Medium Early 58.0 c 90.0
Bluebonnet 50 8990 Southern Long Midseason 57.2 c 110.0
Texas Patna 49 8991 La., & Texas Long Late 51.8 c 58.6 c
Zenith 7787 Southern Medium Early 48.9 c 54.3 c
Nira d 2702 Southern Long Midseason 46.6 c 60.0 c
Bluebonnet d 8322 Southern Long Midseason 34.6 c 25.7 c
a Ormrod and Bunter (1961). b Maturity group in the location in which the variety is
principally grown. c Indicates that the variety is less tolerant than Caloro when comparisons
are made by LSD (5%). d Varieties no longer commercially used in the US.
test of 36 varieties from 8 countries, including Japan and Korea, showed ranges
from 24 to 112 for shoot length and 15 to 122 for percentage of survival. Although,
it is clear that there is a wide range of varietal differences, cold water tolerance at
the seedling stage is not related to cold tolerance at the reduction division stage.
d. Delayed heading. In regions where summers are short, cool weather conditions
may delay growth and, hence, heading. Under such conditions, the rice crop
may ripen at lower temperatures than the usual and may not complete grain filling
before the temperature drops below the critical level for ripening. Raising seedlings
in a plastic-covered nursery in early spring and transplanting right after the
temperature rises to 13°–15°C is one way of providing more warm days and a
greater chance to complete grain filling. There are some degrees of varietal
difference in the ability to grow fast under cool weather conditions (Tsunoda, K. et
al 1966).
e. Low temperature-induced sterility. Rice is most sensitive to low temperatures
(15°–20°C) at the young microspore stage after reduction division. It is less
sensitive just before and at the leptotene stage of reduction division, about 10–11
days before anthesis. This information has been obtained from a very precise
work using uniform, single plant material grown in the phytotron (Satake 1976).