ASPECTS OF THE USE OF SACCHAHUM SPONTANEUM IN THE WEST INDIES PROGRAMME

D.I.T. Walker, D. MacColl and P.S. Rao

I West Indies Central Sugar Cane Breeding Station, Barbados

\

ABSTRACT

Many forms of Saccharum sponfaneum are being used in a ge- netic base-broadening programme in the West Indies. Some pro- blems and preliminary results in this breeding programme are des- cribed. Flowering time is broadly related to the latitude of origin; most forms have responded to photoperiod manipulation. About 90% of hibrids have 2n+n chromosome contributions from noble and spon-

1 taneum respectively. Nobilisations exhibit a wide range of adapta- bility fibre and sugar contents, those from certain sponfaneum being superior and others inferior. Resistance to smut disease in nobilisa- tions was overall low, but a few sponfaneum or combinations among pairs of sponfaneum may be more promising sources of resistance.

INTRODUCTION

It is well known that India and Java were the pioneers of interspecific hybridisation in sugarcane. The genetic base of nearly all commercial sugar- cane throughout the world at the present time rests on the two wild parents used by these breeders - S. spontaneum Coimbatore Local, from the neighbourhood of the Coimbatore breeding station; and the Java form of S. spontaneum introduced mainly through Kassoer, a natural F1 (Arceneaux2) .

The recognition that the genetic base is so narrow, and the possibility that other wild clones of the same species might contain a useful extension of variation for such features as disease resistance and adaptability to mar- ginal environments, has encouraged breeders in the U.S.A.4 and the West Indies12 in particular to start new breeding programmes with S. spontaneum. The Spontaneum Expedition Scheme sponsored by the Indian Government in the late 1950's has drawn together a particularly useful collection of forms from all latitudes of India, from a wide range of ecological conditions, and with a range of chromosome numbers. Collections have also been;made in other parts of S.E. Asia and in East Africa.

292 PLANT BREEDlNG

Roach9 crossed two nobles with each of four sporzfaneums and found that the hybrids performed as follows:

below mid-parent: fibre % cane I close to mid-parent: stalk thickness, flowering time, total sugars % cane above mid-parent : tillering

positive heterosis: stalk length, yield ol cane, % flowering, pollen production and reducing sugar % cane.

Observations of some of these and other characters in the West Indies base-broadening programme are discussed here.

OBSERVATIONS ON FLOWERING BEHAVIOUR

1,' Our collection of S. spontaneum clones originates from latitudes I I

between the equator and 32O. In Barbados (13.04ON) they have a wide range of flowering times, but to allow the use of a clone in the breeding programme it must be made to flower in late October or November. In Table I the clones are classified into 10 groups according to their flowering behaviour. The table shows their latitudes of origin and flowering times in Barbados for the 5 years 1972-1976. Notes on each group follow.

Group 1

Contains only SES 154B. Date of flowering can be controlled to some extent by planting or ratooning date. Unlike the clones in group 2 it flowers heavily every year. May be unresponsive to night light break but this has to be further tested. Has not so far been used in the breeding programme.

Group 2

The clones in this group flower erratically from year to year both with regard to first emergence (July or August) and intensity (none to fairly heavy). It is likely that the longest days in Barbados are just marginal for induction and there is probably little difference between this group and certain clones in group 10 e.g. SES 208A and SES 366. The group can be made to flower in November by giving a night light break from May until August followed by early morning light extension from August 20th to a daylength of 13% hours decreasing there-after by the natural shortening of evening light.

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D.I.T. WALKER, D. MACCOLL AND P.S. RAO

TABLE I. Classification of S. spontaneum clones according to their flowering behaviour in Barbados.

Group Clone Lat i tude Dates of f i r s t inf lorescence emergence Range of o r ig in (daylmonth) (days)

1972 1973 1974 1975 1976

SES 1 5 4 ~

SES 178 SES 194 SES 197A SES 208 SES 278 SES 351

SES 205A

SES 289A

Formosa 4 SES 189 Phi l ippine Wild

Pasuruan Ruteng Flores NG 51-25

Tukuyu 2 Suk I s i o l o Kawanda

SES 50 Tabongo Panama Kloet SES 49 Co l o c a l SES 88C US 56-19-3 SES 21 SES 239/43 SES 70 SES 1 4 7 ~ Mapangat Minahasa

SES 76 SES 528 SES 90 SES 567 SES 84/58 SES 91 Dacca SES 602 SES 66 Moentai SES 44A

SES 2 0 8 ~ SES 310 SES 317 SES 366 ss 6411 Burma NG 51-88

294 PLANT BREEDING

Group 3

Contains only SES 205A. This clone flowers over a long period of time in the field (April-October) but flowers only sparingly if at all in containers. Has not so far been made to flower in November but has been used in the breeding programme through some October arrows from the field.

Group 4

Contains only SES 289A. This is a recent introduction. Flowers spar- ingly but continuously from ~ejCi't"ember to December and again by April. Must undergo inductioil under almost all daylengths in Barbados.

Group 5

The clones in this group flower heavily and at a reasonably predictable date each year. Can be made to flower in November by giving a night light break from midJune to mid-August followed by morning light extension to a daylength of 13 hours decreasing thereafter by natural shortening of evening twilight.

Group 6

Contains four African clones. Bate of earliest emergence varies from year to year and can be coiltrolled partly by planting date. Flowers continue to emerge in small numbers for a long period (up to January), and this is distinctly different from all other groups.

Group 9

Normally flower reliably and heavily during early November and therefore require no treatment. Early flowering of SES 239/43 in some years nay be from spring initiation and cutting back in spring should therefore be delayed'until late April for this clone.

Group 8

Flower reliably and heavily after the middle of November but are too late for many of the S. officinaruni clones. Can be made to flower earlier by reducing the daylength from mid-August onwards to 12 hours. This is done by wheeling plants into darkroom at the required time before sunset and taking them out again about 1 hour after sunset.

I l

I I D.I.T. WALKER, D. MACCOLL AND P.S. RAO 295

Group 9

Flower reliably and heavily in late November and early December and are therefore too late lor almost all the S. officinarum clones. Their flower- ing time can be brought forward by the same treatment as for group 7.

Group 10

This includes the clones which under Barbados conditions are non- flowering. SES 208A and SES 366 have been made to flower in November by the same treatment as that given to group 2. SES 310 and SES 317 have received the treatment but did not respond. SES 317 produced one completely sterile inflorescence in September in one year without any treatment. SES 310 has never flowered in Barbados. It may require longer daylengths than 13% hours.

Generally the flowering behaviour of the SES clones is related to their latitude of origin. Clones from latitudes above 26.0°N tend not to flower in Barbados. Exceptions to this are SES 205A and SES 289A, both of which seem able to flower in a wide range of daylengths, and SES 351 from 32.1°N which flowers fairly heavily in August. Clones from latitudes between 20.0°N and 25.0°N flower in late July, August and September. An exception to this is SES 567 from 21.7ON, which flowers in the second half of November. Clones from 10.OON to 12.0°N flower in November, at the same time as the commercial and noble clones in Barbados. Clones from latitudes below 10.OON tend to flower in late November and early December.

Hybrids from these clones crossed with S. ofjicinaruml tend to flower around the mid-parent date, that is, later for the early-flowering groups, and slightly earlier for the late-flowering group.12

I OBSERVATIONS ON CHROMOSOME NUMBERS AND TRANSMISSION

Great interest centres round the transmission of diploid gametes from the nobles (S. officinarum) to many of the first and second generation hybrids with S. spontaneum. We are using as parent S. spontaneum clones with chromosome numbers ranging from 211 = 40 to 2n = 136. Furth- ermore, in order to introduce as much variability as possible from S. of- ficinarum into the hybrids, we have had to use many male-fertile noble clones as females - male sterility is rare in this group - with the con- sequence that we have ,hade some self pollination. Selfs are not always accurately identified by appearance, particularly in backcrosses. For these reasons we are anxious to obtain accurate somatic chromosome numbers in FI's and backcrosses in the base-broadening programme.

296 PLANT BREEDING

TABLE 11. Chromosome tratlsmission in S. officitrurutt~ x S. spotrtut~eutti crosses. I I Spontanewn parent 2n F1 hybrids with To ta l clones counted

n + n 2 n + n

-4s i an mainland

SES 49 62 1 11

SES 66 64 1 2

SES 70 64 0 1 1

SES 84/58 64 1 1 6 17 1 I SES 88C 64 0 13 13

SES 205A 64 0 12 12

SES 366

SES 567

Co l o c a l

Indonesian

Mapangat Minahasa 80 1 4 5

Tabongo 80 1 8 9

Other ' --

Formosa 4

i Proportion of hybrids 7% 93% 99

In Table TI the frequency of hybrid clones with n+n and 2n+n chromosome complements among the F, progeny from various noble x ~pontaneum crosses are given. In fact in many cases the hybrids of the n+n group have one or two chron~osomes less than the expected number; si- milarly the 2n+n group contains many with 2n+n - 1, 2n+n - 2 or 2n+n - 3. More rarely there is a corresponding gain of one to three chromosomes. It is seen that 93% of the hybrids have 2n+n. Earlier re- I

ports of Prices quoted an average of 98%, but Roachlo found only 70%. The loss of a few chronzosomes could have occurred either in the pollen or in the egg. Our somatic chromosome counts in polycross progeny of S. oflicinarum (2n = 80) have revealed some with numbers as low as 2n -;= 70, suggesting that chromosome loss is not uncommon in this species.

D.I.T. WALKER, D. MACCOLL AND P.S. RAO 29 7

We have only counted small samples, but so far we have no evidence in the spontaneums as a whole that the frequency of n+n transmission varies with the cross, whereas Roachlo, from certain other noble x spon- taneum crosses, found ilf n and 2n+n with equal fre'quency. These dif- ferences in frequency are consistent with the hypothesis that there are chance random accidents in gamete formation and fertilisation, with a va- riable but generally rather strong, selection for 2nfn zygotes.

In appearance the n+n hybrids are thinner and smaller than their 2n+n siblings. Nevertheless, some have been selected for further breeding. Phenotypic expression of spontaneum characters in the subsequent segrating backcross families from these should be more evident because of the lower proportion of officinarum chromoson~es than in the noble x (211-1-11) backcrosses.

ADAPTABILITY TO DROUGHT AND WATERLOGGED CONDITIONS

In the Caribbean, drought is a major problem in several member countries (Barbados, Dominican Republic, Guadeloupe, Venezuela) where cane is grown without supplementary irrigation. At the other extreme, sugar- cane on the flat polders of Guyana are frequently subjected to periods of flooding when rainfall exceeds 600111m per month.

Owing to the problenis of growing the' S. spontaneum clones under field conditions, and in order to examine more variation, the adaptability is being evaluated with F1 and BC1 clones. The clones tested have been selected from segregating fainjlies for thicker stalks, higher % total sugars, lower % fibre and lower % flowering than a random sample of the seedlings. Observations were made in sniall plots, mostly as scores at various stages for growth, and in one case final yield was determined. The drought stress trials were sited on the coast of Barbados, subject to high insolation, long periods of drought and annual rainfalls of ca 800mm. The trial in Guyana was placed on land with the water table more or less at the soil surface from 6 weeks of age. Table I11 draws together the results to give an idea of the differences between the hybrid progenies grouped by their spontaneum parents. Obviously these means mask a lot of variation within families, and individual clones with good adaptability have been found, for example, among Fls from SES 84/58. It is most interesting, from a breeding point of view, to see that adaptability of progeny may not be closely related to the ecological niche of the spontaneum parent.

298 PLANT BREEDING

TABLE 111. Relative ratings (mean 100) of FIS in drought resistance trials and waterlogged triril.

Spontanewn Native ecological r a t i ng % of mean (No. of clones) comments parent niche droughted waterlogged

SES 49 moist sandy riverbed

SES 66 r i c e f i e l d bunds

SES 84/58 ?

SES 8 8 ~ dry wasteland

SES 366 montaine ( ~ e p a l )

SES 567 ,? ? (Burma)

Formosa 4 7

Mapangat Minahasa ? (Sulawesi)

22 clones died i n ratoon a f t e r drought

ANALYSIS FOR TOTAL SUGARS AND FIBRE CONTENTS

TABLE IV. Weighted mean analyses of F1 clones grouped by their spontaneum parents in several nurseries.

Spontanewn parent

No. of fami l ies

Brix % cane

f i b r e % cane

Asian mainland

SES 49

SES 66

SES 84/58

SES 88C

SES 90

SES 567

Indonesian

Mapangat Minahasa

Tabong o

NG 51-2

Other

US 56-19-3

D.T.T. WALKER, D. MACCOLL AND P.S. RAO 299

While it is generally stated that the ability to accumulate sugar in hybrids is inherited from the noble parent, we have also been interested in the contribution of the spontaneum. Brown eE a13 demonstrated conside- rable heritable variation in % total sugars and % fibre within S. spon- laneum.

Table IV gives a summary of analyses from our F, families, derived from several nurseries in which all the more vigorous (and shy-flowering if possible) seedlings have been analysed before making a decision on se- lection. Analyses were made by grinding 5-10 stalks in a Jeffco cutter- grinder, followed by Tanimoto's press extraction methodlJ1. Overall, some 6% of seedlings raised were analysed in this way.

OBSERVATIONS ON SMUT DISEASE IN FIRST GENERATION HYBRIDS

Smut (Ustilago scitaminea) appeared in December 1974 in a major commercial variety in Guyana, and has now also been found in Trinidad and Jamaica. Several other commercial varieties are susceptible, and the disease poses a threat to the whole of the Caribbean region. The West Indies breeding station is also associated with African industries (Nigeria, Zambia, Mozambique) where smut has been a problem for many years. Resistant varieties are therefore of vital interest to us.

With the cooperation of Guyana Sugar Experiment Station, recently selected F, clones representing 31 forms of S. spontaneum have been tested. In April 1975 10-12 cuttings 20-30 cm long were dipped in a spore suspen- sion containing 5.7 x lo6 spores ml-1 for 30 min. and were then planted in short rows in the field. The susceptible variety HJ 5741 was similarly inoculated and planted at intervals throughout the experiment. The plot was inspected on 27 occasions over 37 weeks in the plant crop, and on 6 occasions in the first ratoon crop over 40 weeks. On each occasion whips were counted and removed. The results shown in Table V are calculated from the accumulated totals in each crop.

Out of 132 clones considered only 10 remained uninfected over two crops. The Hawaiian workers have reported5 a reasonably high correlation (r = 0.76) between this inoculation technique and field infection, with a slight bias towards overestimation of susceptibility. They suggest that clones with less than 20% of plants infected by artificial inoculation have zero to 5% infection under conditions of field exposure. Even at this more lenient threshold, alarmingly few of our F, clones appear to carry resistance.

Whip counts are only one criterion of infection. The effect of systemic infection on growth is also variable. In addition to having whips some plants become completely dwarfed and grassy, or contain a mixture of normal canes and grassy shoots. More tolerant varieties appear to produce normal canes with whips restricted to a few later basa14shoots or sideshoots on the larger canes. The experiment was scored forethese effects at 45 weeks of

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300 PLANT BREEDING

age in the ratoon crop, each stool being classified as dwarf, mixed or essentially normal. On this basis (columns 9 and 10 in Table V) there were much more striking differences between clones, but still a disappoint- ingly low level of tolerance. - TABLE V . Frequencies of smut observed over two crops after inoculation in some F, clones, grouped by spontarreum parent.

Average infec t ion r a t e S. spontanewn parent Rating No. of Plant Ratoon Dwarfing (%) Uninfected

of clones % % % % clones pgrent, t es ted s tools s t a l k s s tools s t a l k s severe p a r t i a l (No. ) n a

Mainland Asia

Burma 6 11 68 50 86 49 24 69 Co l o c a l S 6 67 :a45 79 37 12 100 Mandalay 7 3 67 53 70 44 38 59 SES 21 R 3 88 80 100 66 80 93 SES 49 R 8 80 54 78 35 14 70 SES 66 R 3 80 64 63 40 16 loo SES 84/58 14 91 68 96 61 49 77 SES 88c R 7 10 64 43 77 48 27 80 SES 90 S 5 70 48 63 37 22 72 SES 91 S 3 80 66 87 35 39 100 SEX 178 R 2 88 65 loo 73 67 loo S!S 2;5A s 1 2 45 28 65 21 13 33

( ~ 0 1 ~ ) 11 45 38 37 29 23 49 SES 366 7 84 59 70 38 17 61 SES 528 . 1 0 0 0 0 0 0

n i l n i l n i l n i l n i l n i l n i l n i l n i l n i l n i l n i l

2 n i l

1 2

Indonesian

Kloet 1 2 17 2 32 4 0 0 1 Mapangat Minahasa 9 7 21 8 30 9 16 74 1 Moentai 1 4 18 11 28 14 12 62 1 Pasuruan 2 52 34 65 22 17 100 n i l Tabongo 2 8 84 65 82 48 49 89 n l l 51 NG 2 4 87 69 80 52 25 100 n i l

Others - Aegypt icum Formosa 4

1 1 0 0 0 0 0 0 1 4 96 73 94 50 79 IOO n i l

Rtkuyu 2 1 2 84 53 loo 57 13 100 n i l rukuyu 2/SES 205A 3 27 18 53 20 33 67 1 ss 64/1 3 100 80 100 64 55 91 n i l

*A from Rao e t az8 ( ~ n d i a ) and personal communication

*B from Zadd & Heinz ( ~ a w a i i ) 6 ,

This summary neglects the contributions of the female parents, ge- nerally nobles. An independent trial of 49 noble clones, using the same inoculation techniques, indicated similar susceptibility, only 6 remaining uninfected as plants. This is in agreement with Ladd and Heinz6.

Independent reports with complex commercial hybrid populations suggest that the frequency of resistance is much higher - perhaps 30-40%. Furthermore, in a set of con~n~ercial and promising complex hybrids tested in the same experiment as the Fls, though some whips were recorded in more than 90% of varieties, counts were lower, and the1 incidence of dwarf- ing quite rare. In view of the poor performance of Fls and nobles, where

D.I.T. WALKER, B. MACCOLL AND P.S. RAO 30 1

is this resistance coming from? Did our original genetic base fortuitously id- clude resistant noble canes? Has selection (often in the absence of smut tests) somehow improved the level of resistance over the 5 or 6 generations of breeding of present commercial varieties?

A closer look at the parentage of the immune and highly resistant F1 varieties reveals that many of them probably contain more than a single spontaneum background; in some, a commerciai female was used in place of a noble cane, while others are progeny from a polycross among Fls of various backgrounds, selected for their superiority over the parents. Thus all F,s tested from SES 66, SES 91, and Moentai had commercial female parents rather than nobles. All but one of the Burma progeny come from POJ 2725. The inore instructive comparisons are set out in Table VI, quoting only the plant cane data ,for the sake of brevity.

TABLE VI. Percentage stalk infection in simple and complex nobilisations.

Parentage type Clonal progeny s t a l k in fec t ion percentages i n p lan t s

noble x SES 49

commercial x SES 49

noble x SES 84/58

commercial x SES 84/58

noble x SES 90

commercial x SES 90

noble x SES 205A

noble x SES 205A polycross*

noble x Tukuyu ff 2

noble x (Tukuyu x SES 2054.)

zero,. 79.2, zero, 1 .3, 53.2, 39.49 48.8, 1.6, 71.4, 56.7, zero

42.3, 63.8

24.8, 28.5, zero

mean

mean

mean

mean

mean

mean

mean

mean

mean

mean'

-%nost considered t o be combinations with Burma o r Mandalay

The most promising S. spontaneum parents as simple nobilisations would seem to be SES 567 and Kloet, with single progeny evidence also lor SES 528 and Aegypticum. The Indonesian group, with the exception oI Tabongo, appears to carry more tolerance of the dwarfing condition. But possibly the most promising approach to the smut problem in the base- broadening programme would be to look for complementary resistance from complexes of two or more spontaneum.

302 PLANT BREEDING

CONCLUSION

Because we are working on a broad front, our breeding programme has not contained well-designed parent-progeny experiments of the form used by Roachg. However our observations so far are broadly in agreement. To date we have sufficient information from 8 spontaneums to draw some cautious conclusions which can be summarised as follows:

SES 49 has yielded some F1 clones with good adaptability and mo- derate quality; they tend to be heavy flowering, susceptible to smut and in some cases to leaf scald (Xanthomonas albilineans).

SES 84/58 has yielded some clones with excellent adaptability and quality, above average in thickness of stalk, but regrettably these all seem to be highly susceptible to smut.

SES 88C has yielded some vigorous clones, tending to be heavy flover- ing, and with only few of broad adaptability; smut infection was moderate.

SES 91 has yielded thicker Fls below average in analysis and susceptible to smut; their adaptability has not been tested fully.

SES 366 yielded clones of high quality, with early flowering plus a big crop of thick late suckers which grew into harvestable canes by the crop; nearly all are severely infected with smut and leaf scald, and have poor adaptability to marginal conditions.

SES 567 yielded clones of remarkable thickness (much thicker than the mid-parent); quality was high, but adaptability poor; resistance to smut seems to be present.

Mapangat Minahasa yielded tall vigorous progeny, high in fibre with a marked tendency for pithiness, low in quality but with, in many cases, good adaptability and smut resistance.

Tabongo has yielded clones with long canes and average tillering, lower than average in quality, generally drought resistant but badly affected by smut disease.

ACKNOWLEDGEMENTS

We are grateful to Mr. V. Young-Kong and the staff of the ~ u ~ a n a Sugar Experiment Station for running the smut inoculation trial.

D.I .T. W A L K E R , D. MACCOLL AND P . S . RAO

REFERENCES

1 . Anon. (1969). Discussion of analysis methods in Ann. Rep. W.I. Cent. Sugar- cane Breed. Sta. 36:15.

2 . Arceneaux, G. (1965). Cultivated sugarcanes of the world and their botanical derivation. Proc. ISSCT 12:844-854.

3 . Brown, A.H.D., J. Daniels, B.D.H. Latter and M. Krishnamurthi. (1969). Po- tential for sucrose selection in Saccharunt spontaneum. Theoret. Appl. Genet. 39:79-87.

4 . Dunckelman, P.H. and R.D. Breaux. (1968). Evaluation of germplasm in the USDA sugarcane program at Houma, Louisiana. Proc. ISSCT 1 3 : 888-892.

5 . Ladd, S.L., D.J. Heinz, G.W. Steiner, R.S. Blyther, J.C. Comstock and H.K. Meyer. (1975). Natural infection reaction to smut disease. ISSCT Sugarcane Pathologists' Newsletter 13/ 14: 9-10.

6 . Ladd, S.L. and D.J. Heinz. (1976). Smut reaction of non-Hawaiian sugarcane clones. ISSCT Sugarcane Pathologists' Newsletter 17, 6-14.

7 . Price, S. (1963). Cytogenetics of modern sugarcanes. Econ. Botany 17:97-106. 8 . Rao, J.T. and Vijayalakshmi. World catalogue of sugarcane genetic stocks.

Coimbatore, India: Sugarcane Breeding Institute, pp. 77. 9. ' Roach. B.T., (1968). Qzlantitative effects of hybridisation in S. officitlarum x S.

spontaneum crosses. Proc. ISSCT 13 : 937-954. 10. Roach, B.T. (1968). Chromosome transmission in interspecific and intergeneric

crosses. Proc. ISSCT 13 : 900-920. 11. Tanimoto, T. (1964). The press method of cane analysis. Hawaiian Planters Rec.

57: 133-150. 12. Walker, D.I.T. (1971). Utilisation of noble and S. sporitatzeum germplasm in the

West Indies. Proc. ISSCT 14:224-232.

ASPECTOS DEL US0 DE S A C C H A R U M SPONTANEUM EN EL PROGRAMA DE LAS ANTILLAS OCIDENTALES

D.I.T. Walker, D. MacColl y P.S. Rao

RESUMEN

En las Antillas Occidentales se estan usando muchas formas de Saccharum sponfaneum en un programa para ampliar la base genetica. Se describen algunos problemas y resultados preliminares en este 'programa de cruzamiento. El tiempo de floracion es amplia- mente relacionado a la latitud de origen; la mayoria de las formas respondieron bien a la manipulacidn fotoperiodica. Alrededor del 90% de 10s hibridos tienen contribuciones cromosomales de 2n+n de noble y spontaneum, respectivamente. Las nobilizaciones muestran un limite amplio de adaptabilidad, fibra, y contenido de sacarosa; aquellas nobilizaciones de algunas sponfaneum~, son superiores y otras son inferiores. La resistencia a la enfermedad del carbon en las nobilizaciones fue generalmente baja, per0 algunas sponfaneum o combinaciones entre pares de sponfaneum pueden ser fuentes mas prometedoras de resistencia a la enfermedad del carbon.