ABSTRACT

The oleiferous Brassicas including B. juncea (L) Czern, L.) B. rapa (syn. B. campestris L.) and B. napus L. are the important sources of edible oil in India. The world production of rapeseed-mustard has been increasing at a rapid rate in several countries largely in response to the continuing increase in demand for edible oils and its products. The projected demand for oilseeds in India is around 34 million tonnes by 2020, of which about 14 million tonnes (41%) is to be met by rapeseed-mustard. Evidently further enhancement in productivity potential of rapeseed-mustard genotypes is, therefore, essential. The present level of productivity which is about one t/ha. has been achieved mainly through varieties developed by pure line selection from indigenous germplasm and limited efforts are made in intervarietal hybridization in B. juncea. Success has been achieved in reducing the duration of B. juncea cultivars from 150 days to 110 days. Similarly, maturity duration of B. napus lines have been reduced from 160-180 days to 120-130 days with slight penalty for yield. These new genotypes provide greater scope for horizontal expansion of this crop in non-traditional areas. Among abiotic stresses, salinity and drought are the key factors.Genotypes with higher level of resistance to salinity have been developed. To capitalize on the gains of natural out crossing, systematic efforts of developing broad base gene-pools have been found encouraging in B. juncea. Mustard genotypes exhibit tremendous variability in plant types. Medium plant height, early maturity and better response to added input are some of the desired characteristics, which are associated with consistent yield performance over array of environments. Some of the most popular varieties like Varuna tends to lodge under better management conditions which ultimately brings yield penalty. Genotypes with medium plant height appear to be more stable over varied environments. The exploitation of hybrid vigour, through use of CMS and appropriate restorer will go a long way in raising the production potential of rapeseed and mustard in India. Breeding for resistance to Alternaria blight and white rust have so far alluded our efforts. Lines identified with lower level of resistance/tolerance are currently being used to develop populations with multiple genes resistance/tolerance. These and other approaches for raising the production potential of rapseed mustard have been discussed in this paper.

Under the name rapeseed and mustard, seven important annual oilseeds belonging to the Brassicaceae (Cruciferae) are grown in India. They are Indian mustard (Brassica juncea [L.] Czern. & Coss.), commonly called rai (raya or laha), the three ecotypes of Indian rape, B.campestris L. ssp. oleifera viz., toria, brown sarson (lotni and tora types) and yellow sarson, Swede rape or gobhi sarson (B.napus L.), Ethiopian mustard or karan rai (B.carinata Braun.) and taramira or tara (Eruca sativa Mill.). On the Indian subcontinent B.juncea is the dominant species grown and alongwith. B. rapa ( syn. B. campestris L.) and B. napus L. are the important sources of edible oil in India. These species are regarded as of Asiatic origin. Besides, taramira, believed to be a native of southern Europe and north Africa is grown in the drier parts of northwest India. Of late, two other exotics, namely gobhi sarson and karan rai are becoming popular with the farmers in the areas where winter spell is longer. The rapeseed-mustard group of crops are largely grown under the hardy conditions of rainfed agriculture with low input management during rabi season, but have a good inherent potential to convert natural resources into usable biological energy.

PRESENT SCENARIO

Global

Rapseed and mustard crops are being cultivated in 53 countries spreading over the 6 continents across the globe covering an area of 24.2 million hectares with an average yield of 1451 kg/ha ranging from 411 (Russian Federation) to 6250 kg/ha (Algeria) and netted the total production of 35.1 million tonnes. Asian continent alone account for 59.1 per cent of the hectarage but contribute only 48.6 per cent to the world production. Europe contribute 29.7 per cent to the global production while its share is only 16.2 per cent in the total global hectarage. The yield is the highest variable ranging from 411 (Russian Federation) to 3528 kg/ha (France).

Table 1. Continentwise area, production and yield of rapeseed-mustard (1996-97)

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Region Countries Area (m ha) Production (m t) Yiled (kg/ha)

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Africa 5 0.17 0.18 1070

North America 3 5.10 6.63 1300

South America 3 0.03 0.05 1557

Asia 8 14.31 17.04 1191

Europe 32 3.93 10.42 2651

Oceania 2 0.66 0.77 1177

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World 53 24.20 35.10 1451

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Source : FAO Production Year Book, 1997

Among the 7 Asian countries, China and India together account for 95.4 per cent of the total hectarage and 96.7 per cent of the rapeseed-mustard production in Asia. The yield level ranged from 466 (Kazakhstan) to 1889 kg/ha (Korea Republic).

India

India’s contribution to world hectarage and production is 28.3 and 19.8 per cent, respectively, whereas, its share in the total rapeseed-mustard production in Asia is 40.7 per cent from an hectarage of 47.9 per cent. Of the total oilseed production in India, rapeseed-mustard account for 27.8 per cent from an hectarage of 25.6 per cent. In India, rapeseed-mustard are cultivated on 6.68 m ha mainly in Northern plains. Indian mustard (B. juncea) is cultivated in the states of Assam, Bihar, Gujarat, Haryana, Himachal Pradesh, Jammu & Kashmir, Madhya Pradesh, Orissa, Punjab, Rajasthan, Uttar Pradesh and West Bengal.

Table 2. Progressive improvement in area, production and yield of rapeseed-mustard in India between 1985-86 to 1996-97

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Years Area (m. ha) Production (m. t) Yield (kg/ha)

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1985-86 3.80 2.64 674

1986-87 3.73 2.63 700

1987-88 4.51 3.37 748

1988-89 4.83 4.38 906

1989-90 4.97 4.13 831

1990-91 5.78 5.23 904

1991-92 6.55 5.86 395

1992-93 6.19 4.80 776

1993-94 6.29 5.33 847

1994-95 6.06 5.76 950

1995-96 6.66 6.07 911

1996-97 6.44 6.90 1017

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Source : Agricultural Statistics At a Glance, 1998

There has been commendable progress in rapeseed-mustard research during past several years in respect of development of location/situation specific varieties, agro-production and protection technologies, on-farm demonstrations and production of basic and breeder seed. But still there are some researchable issues which cause hindrances in rapeseed-mustard production. Through the past 30 years of research programme on rapeseed-mustard the present level of productivity is achieved mainly through varieties developed by simple breeding methods like pure line selection from indigenous germplasm and limited efforts are made on intervarietal hybridization and other aspect in B. juncea. However, in the present paper in the varietal development programme the following strategic issues are discussed in a view to bring spectacular increase in production and productivity of rapeseed and mustard.

MATURITY DURATION

The crop duration plays an important role in its adoption. Earliness of a variety is a desirable trait to fit in a multiple cropping system. Efforts in the breeding programme aimed at reducing the growth duration of B. juncea from 150-160 days to 120-110 days and B.napus and B. carinata from 180-210 days to 150-160 days has been successful. This has been mainly achieved through successive introgression of genes responsible for earlyness in different genetic backgrounds. Selection of earlyness in the segregating generation through pedigree method has been quite effective. Many of these early types are also short in plant height. The early maturing varieties proved useful in the horizontal expansion of the crop in non-traditional areas. An early B. juncea variety (synthetic early juncea-2) was released as in 1997 for Eastern India, especially to replace low yielding toria (B. rapa var. toria). This variety matures in 110 days as against more than 140 days for Varuna and Kranti. Similarly, the growth duration of introduced B. napus strains has reduced considerably from 160-180 days to 130-140 days as a result of concerted breeding efforts for earlyness with slight penality for yield.

ABIOTIC STRESS

Drought

Rapeseed-mustard were considered to be the crops of marginal and sub-marginal rainfed lands. The situation has changed dramatically in recent times. The irrigated area increased steadily from 14.8% (1967-68) to 66.3% (1995-96). The remaining 34% of the area is rainfed.Drought or lack of moisture at one and more phenological stages caused reduction in seed yield. Although mechanism of drought tolerance has not been well understood yet many drought tolerant cultivars have been developed by selecting and evaluating in the targeted drought prove areas.

Salinity

Salinity is a serious yield limiting factor in many parts of the country. Concerted breeding efforts have resulted in to the development of salinity tolerant cultivars like CS 52. These two varieties have consistently performed better in the salt affected soils than the national checks- Varuna and Kranti. Further studies have shown that amphipolyploid species, viz. B. napus, B. carinata and B. juncea are more tolerant of salinity than the diploid brassicas. B. napus followed by B. carinata have been characterized as more salt tolerant, particularly in climatic zones with long cool periods. B. juncea, probably due to its shorter growth period compared with B. napus and B. carinata, has proved more promising in semi-arid and arid climates with short winters. Brassicas are by and large more vulnerable to alkalinity than to salinity.

Frost

It is not a problem of regular occurrence. In cooler climate of north-western India, the frost from mid December to late January some time causes considerable yield losses. Some genotypes developed by CCS Haryana Agricultural University showed fairly a high tolerance to frost.

BIOTIC STRESS

Pest Resistance

Yield potential of the newly developed rapeseed-mustard cultivars is not realised fully because of the attack by pests such as weeds, diseases and insects. Rapeseed-mustard, in general, is highly vulnerable to diseases and insect pests. The yield losses could be as high as 97% due to aphid (Lipaphis eysimi) insect. The major insects are aphid, painted bug (Bagrada cruciferarum) and mustard saw fly (Athalia proxima). Alternaria blight (Alternaria brassicae) white rust (Albugo candida), downey mildew (Peronospora parasitica) cause appreciable yield losses. Host plant resistance is the logical approach for minimizing the crop losses from pest attack. Donors for alternaria blight and aphids are rare in the present germplasm collection which is the main deterrent to the development of resistant/tolerant varieties for these pests. However, a number of good resistance sources are available for white rust, downy mildew and powdery mildew. Saurabh (RH 8113) showed some tolerance to both alternaria blight and white rust. Recently in 1999, Jawahar Mustard-1 has been released as the first white rust, resistant variety. In the epiphytotic conditions of white rust during 1997-98 crop season this variety was obsrved to be free from white rust infestation during early crop stage and out yielded national varieties Varuna and Kranti.

DEVELOPMENT OF BROAD-BASED INTERVARIETAL HYBRIDIZATION GENEPOOL

Presently efforts have been underway to recombine desirable traits such as quality, yield, diseases and pest resistance and tolerance to abiotic stresses by attempting multiple crosses and parental mating utilizing diverse sources through intervarietal hybridization.

Table 3. Gene pools developed and available for utilizing for different traits

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Character Donors Source of availability

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Abiotic Stress

Drought 2 CCS HAU, Hisar

Salinity 3 CSSRI, Karnal, NDUA&T, Faizabad

Frost 1 CCS HAU, Hisar

Biotic Stress

Disease

Alternaria 16 GBPUA&T, Pantnagar

White rust 21 GBPUA&T, Pantnagar

White rust & yellow seeded 14 GBPUA&T, Pantnagar

White rust & downy mildew 56 GBPUA&T, Pantnagar

Insect pest

Aphid 1

Others

High yield 25 AICRPRM trials

Quality 52 NRCRM, Bharatpur, TERI, New Delhi,

GBPUA&T, Pantnagar

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These gene pools are being evaluated for resistance to different biotic and abiotic stresses.

PLANT TYPE VARIABILITY

Rapeseed-mustard had tremendous variation for agromorphological traits such as maturity, plant height, plant canopy, seed yield and associated characters. Besides the yield potential and stability, germplasm is improved for traits contributing to increased productivity. Physiological characters such as nutrient use efficiency, weed competitiveness, high harvest index, need attention. The rapeseed-mustard crops produce large biomass but fail to translocate it to the sink, resulting in low harvest index. Further due to excessive plant height, varieties tend to lodge under good management of high fertilizer and irrigation. Pusa Jaikisan RH-30 Laxmi and Bio-77 had short plant stature, thus less prone to lodging. Attempts should also be made to breed varieties for response to high nitrogen application which needs tailoring of the new plant type having less secondary and tertiary branching, reduced height, more siliqua, high seeds/siliqua and 1000-seed weight with better nutrient-use efficiency and capacity to transport assimilate to seeds.

Table 4. Variability for agromorphological traits in rapeseed-mustard

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Character Range

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Plant height (cm) 75 - 240

Primary branch 5.0 - 10.8

Secondary branches 12.0 - 34.6

Main shoot length (cm) 44 - 62.9

Siliquae on main shoot 22.4 - 80.0

Seeds/siliqua 10.7 - 18.6

Test weight (g) 2.5 - 8.0

Harvest Index 25.1 - 38.7

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EXPLOITATION OF HETEROSIS

Major constraint for the hybrid development has been the non-availability of a perfect CMS-fertility restoration systems for mustard. The available CMS systems had several limitations like absence of fertility restoration or unstable restoration or biological penalty associated with sterilizing cytoplasm. However, new CMS-fertility restoration systems which are now at final stages of development, appear to be very promising for mustard. Fertility restoration, genetic stability and transferability of gene(s) for fertility restoration introgressed from wild species. In addition, the nuclear background of these CMS will have to be diversified for use in commercial mustard hybrids production.

Concerted effort were made for the simultaneous development of CMS - fertility restorer systems. The approach led to identification of three potentially useful CMS systems (trachy, mori, and Lyratus). Technology to develop GMS/SI based hybrids in yellow Sarson and Toria was perfected. First CMS hybrid PGSH 51 of B. napus was released. Use of somatic hybridization at NRC (Biotech), helped in refining CMS systems like ogu, oxy and trachy.

Table 5. Status of hybrid research in India

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Activity Present Status

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1. Pollination control mechanism

CMS systems 8 - Ogura, oxyrrhina, polima, tournifortii,

carinata, trachystoma, moricandia, lyratus

GMS systems

Toria 2 (GM-1, GM-2)

Yellow sarson 2

Mustard 1

Sallele homozygote (Toria) 23

2. F₁ hybrids

Toria Experimental

Yellow Sarson Experimental

Mustard Low yielding/unstable

Rape (B. napus) Commercial (PGSH-51) (HYOLA-401)

3. Filed plot techniques for seed production

Toria Standardized

Mustard Standardized

Rape (B. napus) Standardized

4. Heterotic gene pools Available

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The breeding research efforts if addressed properly to the above issues will certainly help in enhancing the yield potential in rapeseed-mustard crops.

REFERENCES

1. Anonymous, (1999). Annual Report 1997-98. National Research Centre on Rapseed-Mustard (ICAR), Sewar, Bharatpur-321303 (Rajasthan) India.

2. Hegde, D.M. (1998). Integrated Nutrient Management for production sustainability of oilseeds- A Review. J. Oilseeds Research 15 (1) :1-17

3. Kumar, D. (1995). Salt tolerance in oilseeds brassicas. Plant Breeding Abstracts, 65 (10): 1439-1447.

4. Rohilla, H.R. et al (1987). Losses caused by mustard aphid Lipaphis erysimi (Kolt.)in different Brassica genotypes. Proceeding 7^th International Rapeseed Congress vol. (3&4): 1077-1084.

5. Saharan, G.S. (1992). Management of rapeseed-mustard diseases. In: Advances in Oilseeds Research. (Eds. Drs. D.Kumar & M. Rai) Sci. Pul. Jodhpur, India vol. I, Chapter 7:152-188.