SOME NOTES OF THE INCIDENCE OF DISEASE ANDRESISTANCE TO PATHOLOGICAL AND OTHER

ADVERSE CONDITIONS IN CROPS OF SIND.

BY K. I. THADANI, M.Sc. (TEX. U.S.A.), M.AG.,

Botanist in Sind, Agricultural Research Station, Sakrand.

Received June 17, 1936.

Introduction.

THE possibility of controlling insect pests and attacks by parasitic fungiby means of host resistance has recently come within the purview of theplant breeder and although such studies are only in their infancy they indicategreat hope for advances in this direction. In order to plan a systematicattack on this problem, it is essential to obtain information and collect dataon the various forms existing in crop plants, isolation of unit species in themore promising varieties or types, study of hereditary characters and thereaction of the plant to diseases, pests and environmental conditions. Thesedata have been collected during the course of plant breeding work on themore important crops of Sind and whenever possible observations have beenrecorded on the incidence of disease and attack by insect pests and mortalitydue to other causes, e.g., adverse soil and weather conditions. As a resultof these observations, it has been possible to eliminate certain types or varie-ties which were found to be susceptible to these troubles and at the sametime discard certain progeny lines which showed greater susceptibility thanothers. In the plant breeding work at the Agricultural Research Station,Sakrand, a few plants are selected in all the strains every year which conformto the type and are free from disease. The selfed seed of the selected plantsis grown in line cultures in the following year. The best line culture isretained for further testing next year. This continuous maintenance ofsingle plant tradition both in the selected strains and hybrids, has greatlycontributed to the production of improved strains suited to the local condi-tions.

Varietal adaptation and stand of crop in cotton.—In Sind it has beenfound that the germination of cotton is as a rule good but it is difficult tomaintain a good stand in exotic cottons. Considerable mortality takesplace for one or more causes among which may be mentioned high tempera-tures, hot winds, white-ants, root rot, etc. Counts of final stand showed

470

Notes of Incidence of Disease and Resistance in Crops of Sind 471

that 25 % of the plants survived in Egyptian cottons, 58 % in Punjab Ameri-cans and 75% in the improved Sind deshi 27 W. N. In botanical selectionfor crop improvement, hardiness to withstand local conditions is an importantcharacteristic to be taken into consideration. A good stand after the cropis well established is an index of hardiness and ability to withstand adversesoil and weather conditions and also insect attack especially by white-antsand fungoid diseases, like root rot. In a varietal test conducted at theSeed Farm, Mirpurkhas, in 1932-33 the number of surviving plants wascounted at the time of the first picking. The following table shows theresults :—

Due to

Stand of crop. Mean No. ofsurviving plants General

Mean

Standarderror ofmean

Significanceby `Z' test

-Cferencrencl dif

e forsignificance.

(No. ofplants per27 W. N. 289 F-1 285 F-2 285 F-21

acre)

Per plot 975 579.5 765.1 551.5 717.7 219.25 Significantby `Z' test

Per acre ..15600 9272.0 12242 8824 11484.5 on5% 1793.2

Percentage ongeneral mean .. 135.8 80•7 106.6 76.9 100

Percentage oncontrol 100 59 78 56

It will be seen that the improved Sind deshi strain 27 W. N. in pointof stand of crop ranks the highest among the varieties tinder test followedby the improved Sind American strain 285 F-2. This experiment wasrepeated in the following year 1933-34 and the following results wereobtained :—

Due to

Stand of crop. Mean No. ofsurviving plants General

mean

Standarderror ofmean

Significanceby `Z' test

Critical dif-fe^ence for

significance.(No. of

plants per27 W. N. 4 F-98 289 F-1 I Acala 271acre)

Per plot .- 1004.5 693.5 800 625.1 780.7 451.6 Significanton 5%

Per acre .. 21475 14834 17112 13371 16698 level 4518.56

Percentage ongeneral mean .. 128.6 88.8 102.4 80•0 100

Percentage oncontrol .. 100 69.0 79.6 62.2

472 K. I. Thadani

It will be seen that in this season also the improved Sind deshi rankedfirst in point of stand of crop ; but the stand of the crop was on the wholevery much greater in 1933-34 than in 1932-33. The following table willshow the relative stand and the yield of the varieties under test in the experi-ments described above.

1932-33 I( 1933-34

^ `Yield of seed cotton

fYield of seed cotton

Variety Relativestand % Variety Relative

stand Per acre Per plantPer acre Per plantin lbs. in grams in lbs. in grams

27 W. N. 100 1620.0 50•0 27 W. N. 100 1571.2 35.4

289 F-1 59 1321.6 64•8 289 F-1 80 1020•0 28.9

285 F-2 78 1121.6 41.6 4F-98 69 1055.0 34.2

285 F--21 56 840.0 43.2 Acala-27 61 508.0 18•4

It will be seen that the improved Sind deshi, having the highest stand,gives the most yield and although the stand of crop was greater in 1933-34than in the preceding season, the yield, on the whole, was less than that ofprevious year. This experiment was repeated in the third season 1934-35.The results are briefly summarised in the following table.

Due to

Stand of crop. Mean No. ofsurviving plants General

mean

Standarderror of

mean

Significanceby ' z' test

Critical dif-ference peracre for

significance.(No. of

27 W.N. 289 F-1 285 F-2I 4 F-98 plants peracre)

Per plot 402.6 340.1 365.3 408.3 379 253.1 Not signi-ficant

Per acre .. 25763.5 21656.0 23381.3 26133.3 24233.5 5237.1

Percentage ongeneral mean .. 103.1 89.3 96.4 107•8 100

Percentage oncontrol 100 84.0 90.7 101•4

It will again be observed that although the stand of the crop obtainedduring 1934-35 was greater than that of the preceding two seasons, theyield on the whole was much lower especially in the case of 27 W. N. and4 F'-98 as shown hereunder :—

Notes of Incidence of Disease and Resistance in Crops of Sind 473

Yield of seed cotton

Variety Relative stand%

Per acre in lbs. I Per plant itgrams

27 W. N. .. .. 100.0 628 11•03

289 F-1 .. 84.0 676 14•30

285 F-2 .. .. 90.7 731 14•20

4 F-98 .. 101.4 621 10•76

The low yield in spite of good stand of crop was probably due to heavyshedding of buds and flowers caused by the continuous cloudy weather inthe months of July-August and part of September. The cottons which wereeither very early in flower, viz., 285 F-2 or very late in flowering, viz., 289 F-1were less affected than the other two cottons, viz., 27 W. N. and 4 F-98which occupy an intermediate position in point of flowering period. Thisis a case in which seasonal variations have brought about reduced yield inspite of good stand. It may be noted that in order to cultivate exoticcottons in Sind successfully, it is essential to obtain a good stand.

The other important characteristic which is most desirable in a cottonvariety to be grown in Sind, is its resistance to a peculiar condition of theleaf caused by jassids, or other organisms or otherwise commonly .knownas the `red leaf' disease. Most of the imported American cottons possessingleathery and glabrous leaves have been found to be so affected. The PunjabAmerican cottons are also affected but some of the strains derived from themand selected for resistance to this condition have proved to be very suitablefor growing in the Barrage areas of Sind. Thus the selected strains of SindAmerican cotton, viz., 289 F-1 and 4 F-98 are the best strains in thisrespect so far obtained. These selected strains are being multiplied.

Another peculiar condition which has been noticed among the Egyptianand Sea Island cottons tried in Sind is the `leaf crinkle'. Most of the varietiesso far tried in Sind, e.g., Sakel, Pima, Yuma, Maarad, and Sudan cottons,have been found to be so affected. The only varieties which were found tobe less affected are :—(1) Ashmoni, (2) Zagora Melaky, (3) Sea Island. Inthese three varieties selection has been made for resistance to this conditionand as a result of the work of selection and acclimatisation three improvedstrains of cottons, viz., Ashmoni 37, Boss III-16 and Sea Island 2-4 havebeen produced, which can be grown successfully in Lower Sind.

S4 >!

4^4 'K. I. Thadani

Incidence of long smut (Tolyposporium filiferum) of jowar :—This fungoiddisease is common in Sind and the extent of damage varies with the season.Counts taken in cultivator's field on 500 earheads in the year 1926-27 showedthat the smut-affected grains in an earhead varied from 0 to 70 grains,the mean being 8 grains. Considering the large number of grains formedin an earhead exceeding 2.000 in the local unselected variety, the percentageof smut attack is indeed small. In the same year the counts of smuttedgrains were taken in line cultures of 14 Sind varieties and results are shown

hereunder :—

Variety

No. of grains perearhead

Smutt % Variety

No. of grains perearhead

Smutt

Sound I Smutted Sound I Smutted

Allakh •. 3575 13.2 0.37 Bagdar .. 3767 70.2 1•83

Sakrand JanapurLocal •. 3677 15.1 0.41 Red •. 2908 66.4 2.23

Acho Bazigar . 1913 10.4 0.54 Acho Kartuho 2854 93•2 3.16

Achi Turi 3122 16.8 0•53 Saoro Kartuho 2145 35.9 3•40

GulmahomedGarhi .. 2149 19•8 0.91 Garho Bazigar 2511 92•5 3•51

Acho Kodri .. 2284 21.9 0.95 Garhi Turi 1438 68.2 4.52

NavabshahLocal .. 2623 25.8 0.71 Red Sathri 2477 '169.0 6•42

It will be seen that some varieties were more affected by `long smut'than others and the highest attack by `long smut' was 6?, %. Breeding ofresistant strains in the more high yielding varieties shown in italics in theabove table has been taken in hand.

In 1932-33 there was a severe attack of `long smut' in grain jowars whichwere in flower towards the end of August or early in September. Twovarieties, viz., Bagdar No. 1 and Saoro Kartuho No. 1 which, as a rule,mature late were badly affected in plots which had been sown in the lastweek of June (30th June) but were comparatively free from the disease inplots sown in the second week of June (7th to 12th June) a fortnight earlier.All the jowar varieties which were in flower before 3rd week of Augustseemed to have escaped this trouble. Similar observations were recordedin the following year. In a plot sown on 8th June with Bagdar variety,

Noles of Incidence of Disease and Resistance in Crobs of Sind 475

28 % of the earheads were affected with long smut while in another plotsown on 22nd June a fortnight later than the former with the same variety,44 % of the earheads were so affected. These observations indicate that themost suitable date for sowing late maturing varieties, viz., Bagdar, SaoroKartuho and Acho Kodri is during the first ten days of June so as to avoidthe attack of long smut.

Incidence of stem borer (Chylo simplex) of jowar.—As a rule jowar cropis practically free from borer attack but this pest causes damage in certainseasons. During the last 9 seasons, the crop was badly affected in twoseasons only, viz., 1930-31 and 1933-34 and yield was greatly reduced.Counts of affected plants were taken in 1933-34 on a number of establishedstrains and hybrids and most of them showed 47 to 71 % attack. Only twostrains, viz., Allakh No. 2 and a hybrid derived from it, viz., Allakh x TorhNo. 5-54-3-39-109 showed 25 and 29% attack respectively. The former isa good quality jowar and the latter has both high yield and superior grain.The value of a variety cannot be determined entirely by its ability to resistattacks of pests or parasitic fungi but other physiological characters suchas yield, quality of grain, etc., demand attention.

Study of `rati' (brown spot) and semi-sterility in rice varieties.—Thebrown spot disease of rice known locally as `rati' caused by Helmintho-porium oryzce has been a very serious disease in Upper Sind for a long time.It affects the crop in the later stages of its growth in September and causessterility of the earhead and shrivelling of the grain thus reducing the ultimateyield of the crop. The disease is extensively carried from season to seasonby means of seed, infected with the fungus spores, but secondary infectionfrom the soil does take place. The attack of the disease was found to bemost severe (a) on late varieties of rice, (b) in low lying and shady areas,(c) under humid conditions with low temperatures. To check the spreadof the disease, several methods of seed treatment were tried. They didcheck the primary infection, but not the secondary infection from the soil,air and irrigation water. Breeding of `rati' resistant varieties has givenquite promising results as shown in Tables I and II. Sterility, commonlyknown in Sind as `khas', is a condition in which the grain fails,to set; whollysterile heads are rare in Sind even in a year when `khas' is prevalent. Thepercentage of sterile flowers varies in different varieties and from season toseason. In spite of this variation this character has been found to be here-ditary and for convenience varieties have been grouped as follows :-

(1) Varieties with low sterility—Produce less than 10% sterile grains.(2) Varieties with medium sterility—Produce between 10-20% sterile

grains.(3) Varieties with high sterility—Produce more than 20 % sterile grains.

476

K. I. Thadani

TABLE I.-1933-34.

Rati attack % Sterility % Yield of main culmearhead in grams

Check Check CheckNo. of

I earheadsVariety Kangni-27 Kangni-27 Kangni-27 I examinedCross Parent

(Mean of CrossI Parent

(Mean of Cross Parent(Mean of

in crosses

100 J 100 100earheads) earheads) earheads)

Plot No. I.Kangni 27 X Kolumba cross.

28-889-56 11 21 9 16 3.22 2.21 400

38-845-70 13 19 10 15 3•47 2•45 1800

38-845-16 15 13 11 24 3.55 2.45 900

Plot No. II.% ^^o %

0/

38-845-86 25.5 30 9 12 2•90 2.01 200

34-267-51 26 38 24 12 2•34 1.45 1100

Ka' i gni 27 x Torh No. 1 cross.1

16-1-28 34 26 12 13 1.76 1•81 100

TABLE II.-- 1934-35.

Rati attack% Sterility °o Yield of main culmearhead in grams

Check Check Check No. ofe sVariety Kangni 27 Kangni 27 Kangni 27ex

x amiami

nn ed

Cross Parent(Mean of Cross Parent

(Mean of Cross Parent(Mean of in crosses

100 100 100earheads) earheads) earheads)

Kangni 27 x Kolumba cross.

28-889-56 5 8•5

38-845-70 5.3 7.5

38-845-16 5 7.5

34-267-51 7 8

Kangni 27 x Torh No. 1 cross.

16-1-28 6 I 7

%12 14 3•29 2.85 200

8.7 14 4.40 2.67 300

8•0 12.5 4.44 2•76 500

8 12 3.78 2.86 200

11 1 10 1 2.34 I 2.79 I 100

Notes of -Incidence of Disease and Resistance in crops of Sind 477

Observations were recorded by the Rice Mycologist on incidence of`rati' and 'khas' in some of the line cultures grown in the Botanical Sectionarea in the year 1933-34 and 1934-35. Main culm earheads were examinedin some established rice strains and hybrids.

Taking into consideration the characters of the parents, it may be notedthat Kolumba 184 is more susceptible to semi-sterility and `rati' diseasethan Kangni 27 which in point of yield also is superior to Kolumba 184and Torh. Hence in studying the incidence of attack, Kangni 27 which wasgrown side by side has been kept as a check. It will be seen that the hybridstrains show on the whole less attack by `rati', less sterility per cent, in theearhead and higher yield. By proper selection of plants, it has been possiblethis year to show a distinct improvement in the more promising types asregards resistance to `rati' over the results of last year. Breeding of resistantstrains is being done by the Rice Mycologist in collaboration with the Botani-cal Section. Testing of resistant progenies for several generations in thefield and artificial inoculation to test susceptibility will form the main lines

of work.

Tolerance of rice varieties to `kalar' in the soil.—Preliminary observationson tolerance of rice varieties to presence of salt in the soil were made in theyear 1932-33. Three varieties of rice, viz., Torh, Lari and Kalanghowell known for their `kalar' resisting power were tested with the improvedstrain Kangni 27 in a plot of land badly infested with `kalar' and measuring8th of an acre in four replications, the unit plot being 11128th of an acre.The following yields were obtained :—

Mean yield in lbs. Critical dif-

Standard Whether ference byDue to

meansignificant Z test.

Kangni Torh Lari Kalangho27 mean error by Z' testy

Yield inlbs. per acre

Per plot 9.88 9.69 10•25 8•06 9.47 6.22 Notsignificant

Per acre .•1254.4 1228.8 1305.6 1100.8 1211.9 635.4

Percentage on gene- 103.5 101.4 107.7 90.8 100

ral mean

The following stand of crop as judged by the number of plants surviving,

was obtained :---

478 K. I. Thadani

Variety Stand per cent. Variety Stand per cent.surviving plants surviving plants

%Kalaugho 76.6 Kangni 59.0

Lari 73.9 Torh 68.7

In the following year 1933-34 five main varieties of rice, viz., Kangni 27,Prong 36, Bengalo, Torh and Jajai 77, along with seven selected strains ofrice hybrids, were grown in strips of 7 rows each in a plot of land measuring2/5th of an acre badly infested with `kalar'. The following results were

obtained :—

Variety stand °o Yield of grainper strip in lbs. Variety Stand %% Yield of grain

per strip in lbs.

Kangni x Torh cross.

Torh 57 36.0 16-1-28-11 57-6 36•0

Bengalo 55 31.0 16-1-28-80 54.7 33.4

Kangni 27.. 45.8 32.4 Kangni x Kolumba cross.o/

0

Jajai 77 30.2 18.2 38-845-70 43.6 27.4

Prong 36 25.3 19.4 38-845-86 36.5 26.4

38-845-16 34.1 26-4

28-889-56 25.8 14.4

34-267-51 26.2 19.0

As these results pertain to single plots it is difficult to judge accuratelythe `kalar' resisting power of the varieties, but these preliminary observationsdo indicate that high quality rices, namely, Jajai 77, Prong 36 and hybrid28-889-56 with the exception of Bengalo show least resistance to `kalar'.Torh variety and hybrid strains derived from it show the highest standper cent. and greater yield of grain.

During the year 1934-35 five main varieties of rice, viz., Kangni 27,Jajai 77, Prong 36, Bengalo and Torh together with five selected strainsof rice hybrids were grown in duplicate strips of ten rows each in a plot,measuring 2/5 acre, badly infested with `kalar'. The following results were

obtained :—

Notes of Incidence of Disease and Resistance in Crops of Sind 479

Average of two plots II Average of two plots

Variety Stand % Yield of grainper strip in lbs. VarietyI Stand % Yield of grain

per strip in lbs.

Kangni x Kolumba cross.Kangni 27 .. 80•5 42.0

38-845-70 66.5 22.5Jajai 77 83•0 43.0

38-845-16 62.0 37.0Prong 36 82.5 40.5

28-889-56 58.0 37.0Bengalo 80.5 40.5

34-267-51 59.0 27.0Torh 72.0 43.5

Torh X Kangni cross.

16-1-28 ( 68.0 43.0

It will be seen that the Torh variety and the cross Kangni x Torh, inspite of low stand, have given the highest yield. In the preceding year thesetwo rice varieties had stood highest in point of both stand and yield. Theother rice types which stand 'kalar' well are Kangni and Bengalo confirmingthe observations made last year.

Susceptibility to frost.—Rabi (cold weather) crops are liable to the attackof frost in Sind in certain seasons. It has been noticed that frost occursin two out of five seasons. There are two periods when frost may occur,(1) end of December—early January, (2) end of January— early February.The latter period is more frequent and does the most damage. Wheat isthe major rabi crop in Sind. All varieties of wheat so far tried in Sindare affected by frost if the plant is in flowering stage at the time of theoccurrence of frost. Hence, in order to escape frost in Middle and NorthSind indigenous wheats should be sown in the latter part of November sothat they come in flower when the danger of frost has passed. Wheat cropis sometimes affected by rust disease, especially the late sown crop.Several varieties of wheat have been tested. The improved strains ofwheat selected from indigenous crop have been found to be less susceptibleto rust than the local selected varieties. Several varieties of wheat fromdifferent parts of India have been tested. Pusa 114 wheat has beenfound to resist rust attack considerably and is decidedly superior toother improved strains evolved in Sind and the Punjab. Owing to the lowprices obtained for wheat during the last few years attention has been

480 K, I. Thadani

given to the investigation of alternative money crops to wheat.Cruciferous oil-seeds have been found to be much more profitable thanwheat, provided they are not hit by frost. Sowing date experiments havebeen conducted at Sakrand for North and Middle Sind and the results indicatethat early varieties of Torio (Brassica Napus var. dichotoma), viz., Lyallpurtypes and Kazi Ahmed variety should be sown in September so that theyare actually harvested before the frost occurs. On the other hand, latetypes of Torio, viz., Halla and Mirpurkhas are best sown in end of Octoberso that they will come in flower after the frost period has passed. Similarly,rape-seed (Brassica camp estris var. Sarson) should be sown during the firstfortnight of November since earlier sowings are as a rule affected by frostand mustard (Brassica juncea) is best sown in the month of December.Late flowering varieties of linseed, viz., Pusa H-68, Pusa H-12 and Hallaescape frost when sown in the end of October. The investigations carriedout at the Agricultural Research Station, Sakrand, clearly indicate that oil-seed crops possess a wide range of sowing period which enables the culti-vators of these crops to make full and economic use of irrigation waterand at the same time arrange the time table of sowings in such a way soas to avoid frost attack and get the best returns.

Frost resistant types of oil-seeds.—No frost resistant types were foundin Torio (Brassica Napus var. dichotoma), Jambho (Eruca saliva), Rape(Brassica campestris var. Sarson) and Mustard (Brassica juncea) varietiesimported from different parts of Sind and other Provinces. The safflowercrop is affected by frost in Sind even before the flowering stage. Amongthe various types of safflower obtained from Pusa, Deccan and GujratPusa types Nos. 9, 17, 18 and 19, and Dholka No. 1 and 2 were found toresist frost attack.