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30 THE BRITISH SMUT FUNGI Tyler, 1938); S. cruenta (Rodenhiser, 1932, 1934); Ustilago longissima (Bauch, 1931, 1932 b; Kammerling, 1929); Sphacelotheca schweinfurthiana (Bauch, 1932 c); Tilktia caries and T.foeiida (Flor, 1932 a, 1933). The number of factors, not yet known with certainty in any species, usually increases when a vddev range of material is examined (Becker, 1936). In Ustilago maydis, a muchstudied species, at least 63 factors governing compatibiHty have been detected. Factors governing the fusion of gametes are not usually linked with cultural or pathogenicity factors (Christensen, in Stakman et al., 1929; Stakman et al., 1929; Dickinson, 1931; Bauch, 1922, 1927; Alhson, 1937; Rodenhiser, 1934; Flor, 1933). Kziiep (1919) found, however, a physiological difference between the A and B sporidia of Ustilago violacea (from Dianthus deltoides), one type failing on malt agar, while the other flourished on that medium. Thren (1937) found that haplonts of U. nuda, designated 'plus', could be distinguished from 'minus' haplonts by their stronger growth on malt agar, while on potato agar the 'plus' type failed to grow. The first experiments on compatibility stopped at the initial fusion of sporidia, but subsequent work, and especially that on interspecific crosses, suggests that fusion is not by itself proof of complete compatibility, which alone leads to successful invasion of the host and the maturation of chlamydospores. Fischer (1940 a) found, on the evidence of sporidial fusions, a high degree of compatibility between Ustilago striiformis from Elymus glaucus and Ustilago bullata from several hosts. In some of the successfully paired lines infection hyphae developed in great numbers, while in others growth ceased after the fusion of sporidia. Cultures of U. striiformis, in the same compatibiUty group, always behaved in the same way when paired with different lines of U. bullata. Fischer accepts these two types of behaviour as comparable to those discovered by Bauch (1932 c) in his intraspecific matings of Sphacelotheca schweinfurthiana. Chlamydospores of the hybrid Ustilago striiformis x U. bullata have not yet been obtained, but it is not unlikely they would develop on appropriate hosts from lines that gave the infection hyphae. Races of Ustilago avenue from oats and tall oat grass have no common host. Their sporidia are compatible and suitable combinations of monosporidial lines, one from each race, produced what appeared to be hybrid chlamydospores on wild oats (presumably Avenafatua). Among 16 compatible inter-racial matings used to inoculate wild oats, tall oat grass, and Anthony oats {Avena sativa), four produced smut on the first host and none on the last two. Chlamydospores only developed from the paired lines in which fusion was followed by the growth of infection hyphae. These two types of compatibility were not evident in matings within the race from tall oat grass, but they were met again when this was crossed with races of U. hordei from oats and barley. When Fj chlamydospores from wild oats were sown on the three hosts named above, smut was produced on Anthony oats showing that segregation for pathogenicity had occurred. The mode of inheritance of the two types of compatibihty is not yet known (Holton & Fischer, 1941). THE GAMETOPHYTE IN CULTTJBE Monosporidial colonies of a single species grown on a flat agar surface have been found to differ in colour, topography, margin, consistency, rate of gro^vth,
GENETICS • 31 direction of growth, tendency to sector, response to temperature, and response to hydrogen-ion concentration in the medium. Few, if any, of these characters are linked, and a species hke Ustilago maydis comprises many hundreds of different cultural types (Stakman et al., 1929; Christensen & Rodenhiser, 1940). Dickinson (1931) studied the segregation in covered smut of oats, of wide or narrow margin, brown, yellow, or cream colour, corrugated or depressed centre, dry or moist surface, and rate of growth at pH 5-5. Apart from size of margin, which gave a 2:2 ratio, the results suggested that segregation was governed by multiple factors. This holds also in other species, and cultural characters are not usually Unked either with incompatibility or pathogenicity. They are as a rule no guide to the identification of physiologic races (Becker, 1936; Utter, 1938), nor can they be used to separate closely related species (Kienholz & Heald, 1930). To be of permanent value, descriptions of growth in culture should be supplemented by photographs, coloured if possible. Plates illustrating some cultural types have been published for the following species: Ustilago maydis (Stakman et al., 1929; Christensen, 1931), U. avenae and U. hordei (kolleri) from oats (Dickinson, 1931; Western, 1936; Holton, 1931 b, 1932), U. hordei from barley (AUison,1937), U. striiformis (Fischer, 1940a), Sphacelotheca sorghi (Rodenhiser, 1932, 1934; Tyler, 1938), Sorosporium syntherismae and Sphacelotheca destruens (Martin, 1943), Tilletia caries (Kienholz & Heald, 1930). The fuUest account of biotypes in any one species is that given by Stakman et al. (1929) in their study of mutation in U. maydis. Another gametophytic character which has received some study is the degree of sporulation in culture. Some monosporidial lines of U. maydis produce abundant sporidia, some are entirely mycelial, while others are intermediate (Hanna, 1929; Christensen in Stakman el al., 1929, 1931; Stakman ei al., 1929). Stakman (1936) reported on the clear-cut segregation of these growth types. Kemkamp (1939), testing such lines on a wide range of media, found that strictly sporidial cultures could not be induced to form mycelium under any conditions tested. Some intermediates produced more sporidia with a higher concentration of sugars and other changes in the environment. From a cross between two extreme hnes, segregation ratios of 4:0, 3:1,2:2, and 1:2:1, were obtained, indicating that more than two factors govern the inheritance of sporidial and mycelial types. Further studies (Kemkamp, 1942) emphasized the stabiUty of strictly sporidial and strictly mycelial lines but both types are rare, virtually all lines of U. maydis being intermediate. Intermediates can be shifted to extreme mycelial or extreme sporidial by alterations in the environment, but the changes are phenotypic and reversible. The addition of poisons and toxic dyes, reduction of oxygen and nutrients, especially dextrose, stimulated the growth of myceUum. Sectors of myceUum, which sometimes developed in intermediate lines, proved in most examples to be phenotypic, not genie, changes. Unsuccessful attempts to cross strictly sporidial lines revealed the fact that these are incapable of forming myceUum even in the host, but when mated with lines capable of forming hyphae the resulting dicaryophytes were pathogenic. Popp & Hanna (1935), working with the oat race of U. hordei, germinated hybrid chlamydospores from the following combinations of cultural types, sporidial X sporidial, hyphal X hyphal, sporidial X hyphal, and studied the
Page 1 and 2: THE BRITISH SMUT FUNGI ^ (USTILAGIN
Page 3: FOREWORD THIS volume was started wh
Page 6 and 7: 6 PBEFACE We also acknowledge the b
Page 9 and 10: INTRODUCTION THE smut fungi, which
Page 11 and 12: INTRODUCTION H of bushels of wheat
Page 14 and 15: FIG. 1. Vstilago avenae on Arrhenat
Page 16: ^^ THE BBITISH SMUT FUNGI Young hea
Page 19 and 20: BIOLOGY 15 less than the normal, in
Page 21 and 22: BIOLOGy 17 and united with it, fina
Page 23 and 24: BIOLOGY 19 eermination in a collect
Page 25 and 26: BIOLOGY 21 genus, and the manner of
Page 27 and 28: BIOLOGY 23 species of Entyloma, and
Page 29 and 30: 3036^ BIOLOGY 25 in others. Dickins
Page 31 and 32: CYTOLOGY THE discovery of nuclei in
Page 33: GENETICS INCOMPATIBILITY KNIEP'S di
Page 37 and 38: GENETICS 35 when a few sporidia fro
Page 39 and 40: GENETICS 37 lines retained their di
Page 41 and 42: TECHNIQUE COLLECTION AND EXAMINATIO
Page 43 and 44: TECHNIQUE 41 be undesirable. Weak a
Page 45 and 46: TECHNIQUE 43 in one season (see p.
Page 47 and 48: TECHNIQUE 45 barley with loose smut
Page 49 and 50: TECHNIQUE 47 (1939), Holton & Heald
Page 51 and 52: TECHNIQUE 49 Allen's, modification
Page 53 and 54: CLASSIFICATION THE morphological ch
Page 55 and 56: THE BRITISH SMUT FUNGI MOST of the
Page 57 and 58: FIG. 2. Spore geimination in Ustila
Page 59 and 60: THE BRITISH SMUT FUJJGI 57 from one
Page 61 and 62: THE BRITISH SMUT FUKGI 59 of exsert
Page 63 and 64: THE BRITISH SMUT FUNGI 61 noticeabl
Page 65 and 66: THE BRITISH SMUT FUNGI 63 Evidence
Page 67 and 68: THE BRITISH SMUT FUNGI 65 winter in
Page 69 and 70: THE BRITISH SMUT FUNGI 67 Ustilago
Page 71 and 72: THE BRITISH SMUT FUlJGI 69 material
Page 73 and 74: THE BRITISH SMUT FUNGI 71 results o
Page 75 and 76: THE BRITISH SMUT FUNGI 73 TTstilago
Page 77 and 78: THE BRITISH SMUT FUNGI 75 Species i
Page 79 and 80: " TJSE BRITISH SMUT FUNGI 77 Ustila
Page 81 and 82: THE BKITISH SMUT FUNGI 79 On Carex
Page 83 and 84: THE BRITISH SMUT FUNGI 81 Exsiccati
Page 85 and 86:
THE BRITISH SMUT FUNGI 83 Tilletia
Page 87 and 88:
THE BRITISH SMUT FUNGI 85 bunt ball
Page 89 and 90:
THE BEITISH SMUT FUNGI 87 globose t
Page 91 and 92:
THE BRITISH SMUT FUNGI 89 FIG. 13.
Page 93 and 94:
FIG. 15. Spore geimination in Taboi
Page 95 and 96:
FIG. 17. Spore germination in Urocy
Page 97 and 98:
THE BRITISH SMUT FUNGI 95 separate
Page 99 and 100:
THE BRITISH SMUT FUNGI 97 8ori in t
Page 101 and 102:
THE BRITISH SMUT FUNGI 99 Urocystis
Page 103 and 104:
30390 THE BRITISH SMUT FUNGI 101 pr
Page 105 and 106:
FIG. 20. Spore geimination in Entyl
Page 107 and 108:
THE BRITISH SMUT FUNGI 105 Sori in
Page 109 and 110:
On Ranunculus ficariae and B. scler
Page 111 and 112:
THE BRITISH SMUT FUNGI 109 Infectio
Page 113 and 114:
THE BKITISH SMUT FUNGI 111 [Sporidi
Page 115 and 116:
THE BRITISH SMUT FUNGI 113 Ustilago
Page 117 and 118:
REFEEENCES 115 BBETT, M. A. (1940).
Page 119 and 120:
REFERENCES 117 ^ DniON WESTON, W. A
Page 121 and 122:
REFERENCES 119 GRIFFITHS, MAEIOK A.
Page 123 and 124:
REFERENCES 121 HtjTTiG, W. (1933).
Page 125 and 126:
REFEBENCES 123 LiMBOtruN, E. J. (19
Page 127 and 128:
REFERENCES 125 NOBLE, E. J. (1934).
Page 129 and 130:
REFERENCES 127 RoDENHiSEE, H. A., &
Page 131 and 132:
BEFERENCES 129 STAKMAK, E. C, XCEEN
Page 133 and 134:
EEFEEENCES 131 WAXTBE, J. M. (1934)
Page 135 and 136:
INDEX to generic and specific names
Page 137 and 138:
Muscari Ustilago vaillantii, 59 Myo
Page 139 and 140:
Ustilago ficuum Reich., 113 —flps
Page 141 and 142:
2i}:y0 ANDHRA PRADESH AGRICULTURAL
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