Genetical studies of a collection of maize samples

During 1963-1979 a collection of maize germplasm consisting of 1905 samples from 45 countries was studied. The results in detail are included in the book, V. E. Micu, "The Genetical Studies of Maize," published by "Shtiintsa," Kishinev, Mold. S.S.R., U.S.S.R., in 1980. For the Newsletter, a summary of these studies is presented.

In 16,000 progenies from selfing of samples of the collection a very large number of mutants were observed. It is important to note that there were no chemicals applied on seeds or plants, but the old seeds were used for the growing of primary material for selfing. All observed mutants were divided into 5 groups and 86 phenotypical classes, which correspond to well-known mutants. The absolute majority of detected mutants are of the well-known types (Table 1). All the same, several new or little-known phenotypes are also revealed: defective pistils (dep); dichotomously branched plants (dib), absence of tassel (tl); short husks; short leaf sheath; and others. Note should be taken that the frequency of the mutants is clearly lower in dent than in flint samples.

Table 1. List and classification of mutants
 
1. Kernel Form & Texture 2. Pigmentation 3. Leaf Structure 4. Stalk Structure 5. Reproductive Syst. Structure & Function
Type No. cases Type No. cases Type No. cases Type No. cases Type No. cases
bt, sh 27 al 5 ad 36 bk 12 an 28
cp 4 bm 24 cr 19 br 15 ba 64
de 83 f 27 gl 80 bv 1 bd 4
du 2 g 33 Hs 4 d 11 bs 21
et 10 gs 22 Kn 1 dib 6 dep 6
mn 23 ij, j 30 lg 32 la 28 lo, zl 85
o, fl 85 l 91 nl 9 na 2 ms, CMS 44
su 33 li 3 Rg 5 py 4 Pn 2
wx 5 Og 3 Rs 19 zg 8 Pt 4
  272 oy 1 sl 16 others 47 ra 57
    Pg 3 others 65   134 Rf1, Rf2 15
    pm 18   286     rf1, rf2 91
    sr 18         Rf3 11
    v 21         rf3 130
    vp 57         si, pi 15
    yg 7         sk 13
    ys 44         tb 1
    w, lw 140         tl 4
    wd 1         ts 21
    ws 3         ub 8
    zb 19         others 17
    zn 11           641
      581            

In order to determine the inheritance of observed phenotypes the 1446 mutants were examined by elementary genetical analysis. More detailed genetical analyses, including tests for allelism, were conducted for 469 stocks, and clear-cut results were obtained for 428 of them (Table 2).

Table 2. The list of identified mutants
 
Locus No. Cases Locus No. Cases Locus No. Cases Locus No. Cases
ad 5 d1 5 mn 1 sk 13
ba1 7 dib 1 o2 5 su1 27
ba2 5 dep 4 ra1 10 tb 1
bd 1 fl2 2 ra2 8 tl 2
bm1 13 g1 7 Rf1, Rf2 15 ts1 2
bm2 1 la 5 rf1, rf2 91 ts2 7
bm3 3 lg1 18 Rf3 11 ts4 3
bt1 8 lg2 7 rf3 130 wx 3
cms-S 4 Lg3 3        

In general, this research proves once again that local varieties and samples contain great genetic variability which may be used both for further studies and for the improvement of maize.

V. E. Micu

Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors.

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