Rick, C. M.
The stock of this mutant traces to an unfruitful plant of tremendous vigor encountered in a field of var. San Marzano near Clarksburg, California in 1955. All progenies resulting from selfings and hybridization suggest that a single gene is responsible for the hastate phenotype. The total F2 segregation thus far observed in 12 families is 2488 normal: 505 hastate. The deficiency from expected is highly significant but no heterogeneity is indicated between families.
Hastate is immediately recognisable in the first true leaf, which differs from normal in having an entire, elongate, strap shape. Among the genes of similar effect -- c, e, and sf -- ht can be distinguished by its narrower and more elongate primary leaves. Its compounds with c and e have highly modified, reduced leaves. The distinction persists in leaves of the mature plant, which are much less condensed than those of c and e, and are smaller and have fewer segments than normal. The leaf segments are more plicate and acuminate and, with their usual two basal segments, are roughly halberd-shaped.
Most flower buds of ht abort before opening, and the few that open do so irregularly and incompletely. Stamens are variable, often dialytic, twisted, discolored, or otherwise atypical. Pistils appear normal macroscopically, but fruits are more elongate, slender, and pointed than normal. Pollen is usually present in small quantities and ht can be used as staminate or pistillate parent in crosses without great difficulty.
Association tests summarized in the following table give no indication of linkage except with d\1. The departure from random association is significant for 3 of the 4 families tested. The estimated linkage intensities are large (mean = 35 units). Confirmation of this linkage and tests with markers to the left of d\1, would be desirable.
Contingency
Tester + + + t ht + ht t chi-square Co.
a\1 113 41 30 6 1.06
a\1 208 50 45 11 < 0.1
a\1 138 27 40 8 < 0.1
a\1 97 32 18 6 < 0.1
ah 193 65 24 8 < 0.1
ah 97 15 18 10 6.17
c 114 40 32 4 2.84
c 125 40 36 12 < 0.1
d\1 115 39 32 4 2.45 36.0 +- 5.5
d\1 122 48 44 4 7.11 30.0 +- 6.0
d\1 295 135 68 11 9.12 35.5 +- 4.0
d\1 337 118 75 11 6.17 38.0 +- 3.5
dl 196 62 27 5 0.71
dl 95 17 28 0 3.52
dl 430 149 07 38 < 0.01
e 216 42 50 6 0.71
e 91 38 19 5 0.38
rv 79 18 9 2 0.15
rv 102 29 22 6 < 0.l
tf 55 17 8 2 < 0.l
Wo 28 44 3 7 < 0.l
Xa 39 64 5 3 1.0
yv 79 18 9 2 0.15