SEED SCIENCE AND TECH- NOLOGY

1.10.1 Hybrid Seed Production in Vegetables

1.10.1.1 Tomato

Hybrid tomato seed production is primarily taken up in Ranebennur area of Karnataka. With more than hundred private companies taking up seed production, the competition for skilled labour has grown tremendously resulting in high labour cost. Moreover, with the same crops grown continuously for nearly last 25 years, there is increased pest and disease infestation. The cost of hybrid tomato seed being high, it can be a remunerative

business for small to medium level seed companies and rural entrepreneurs of northern India, who cannot afford to take up seed production in Ranebennur. However, owing to extreme cold and frost, seed production in open field conditions in northern India is not remunerative.

Raising hybrid tomato seed crop under low cost poly- house was found to be highly economical and remunerative. The Division of Seed Science and Technology of the Institute developed a complete package of practices following which seed yield of 3.4 kg could be achieved in Pusa Hybrid 4 in a poly-house of 100 sq.

m, which costs about Rs. 50,000/. This results in complete recovery of the cost of poly-house construction in the first year itself and also profits at a selling price of Rs. 20,000 per kg of hybrid seed. The profits accumulate in the subsequent years.

Comparative performance of tomato hybrids developed by IARI in temperature controlled poly-house

Hybrids No. of No. of 100-seed Seed

fruits/plant seeds/fruit weight (g) yield (kg)

Pusa Hybrid 1 34 121 0.349 1.86

Pusa Hybrid 2 29 139 0.372 1.94

Pusa Hybrid 4 44 146 0.407 3.40

This technology is doubly beneficial as it is remunerative to the seed producers, and popularizes public sector hybrids.

Public sector hybrids can bring down the cost of tomato cultivation as the cost of hybrid seed from the public sector ranges from Rs. 20,000 to Rs. 25,000 per kg as compared to the cost of seeds of private sector hybrids which go as high as Rs. 80,000 per kg.

1.10.1.2 Brinjal

Hybrid seed production of brinjal can be undertaken successfully in northern India both under open and net house conditions.

For hybrid seed production in kharif season, a nursery is sown on raised beds between 15^th June and 20^th June and transplanting is done after one month, i.e., between 15^th July and 20^th July, on flat beds maintaining a female to male row ratio of 4:1. For hybrid seed production, pollination should be initiated two months after transplanting on healthy, solitary, long styled flowers. Emasculation should be done in the evening followed by pollination on the next day between 8 A.M.

and 9 A.M. as maximum fruit and seed set occurs when pollination is done on the same day of emasculation.

Maximum fruit and seed setting is achieved in flowers crossed between 15^th September and 15^th October when temperature ranged between 26 ⁰C and 30 ⁰C, and RH between 55% and 70%. For achieving higher seed yield and quality, 5-6 fruits and 9-10 fruits, respectively, should be retained in round and long fruit types. Hybrid fruits should be harvested 65-75 days after pollination, and seed is extracted by cutting fruits in four halves and beating fruits with wooden block, followed by thorough washing and drying.

Hybrid seed production is more profitable in the net house (where the crop is vigorous, insect free, show longer stigma receptivity, pollen viability, higher fruit and seed yields and better seed quality) as compared to that in open field condition. An average hybrid seed yield of 2.0 kg can be achieved from an area of 100 sq. m.

1.10.1.3 Cauliflower

The parental lines, i.e., CC 14 (female) and 18-19 (male), of early group cauliflower hybrid, Pusa Kartik Shankar grown in optimum date of sowing showed non- synchrony in flowering in hybrid seed production. It was observed that the synchronization could be achieved with the application of GA₃@250 ppm to the female line plants at bud initiation (BI) stage, and IAA @50 ppm at curd maturity (CM), bolting and BI stages. Flowering duration (FD) increased by 5-7 days with the application of IAA and GA₃. The problem of non-synchrony can, therefore, be mitigated with the spray of GA₃ (250ppm) and IAA (50ppm) at different stages.

Effect of growth hormones on duration and days to flower in cauliflower parental lines Treatment/stage Flowering duration (no.of days) in female plants

of spray GA₃ IAA Control

(250 ppm) (500 ppm) (50 ppm) (100 ppm)

Bud initiation (BI) 22 28 27 29 Female-23

(151-173) (159-187) (157-184) (158-187) {161-184}

Male-22 {149- 171}

Bolting +BI 26 26 23 24

(160-186) (158-184) (160-183) (157-181)

Curd maturity 30 30 25 29

(CM)+bolting +BI (152-182) (147-177) (149-174) (148-177)

Curd initiation+ 29 24 25 24

CM+bolting +BI (154-183) (158-182) (161-186) (160-184) Note: Figures in parentheses indicate days to flower

1.10.2 Characterization of Isolates of Bipolaris oryzae and their Control

Brown spot of rice caused by Bipolaris oryzae is a major seed borne disease prevalent in all rice growing countries.

Studies were conducted to evaluate rice varieties and different strains of the pathogen and also efficacy of botanicals and bio-control agents in controlling the pathogen in the laboratory test. Twelve isolates of the pathogen collected from different agro-ecological zones were characterized using RAPD markers. The isolates could be grouped into 5 distinct clusters based on 12 selected primers.

Studies on the effect of 8 botanicals and bio- control agents on inhibition of the pathogen strains revealed that patchouli oil @ 1 per cent was most effective against four isolates, followed by citronella oil and lemongrass oil, respectively. Kalisena @ 4 x 10⁸ cfu also resulted in effective control of Bipolaris oryzae.

The study recommended the treatment of paddy seeds with patchouli oil @ 1 per cent for effective control of brown spot disease of rice.

1.10.3 Seed Production Technology of Medicinal Plants

An experiment was conducted to study the effect of three sowing dates and three nitrogen levels on seed yield and its quality in two varieties of isabgol (Plantago ovata L.), viz., GI 2 and Niharika. The crop was sown on November 2, November 17, and December 3, 2007 with three N levels (0, 45 and 90 kg N/ha) during rabi 2007-08. It was observed that delayed sowing adversely affected the seed yield as well as seed quality (as reflected by per cent germination and vigour).

The mean highest seed yield of 706.1 kg/ha in GI 2 and 471.7 kg/ha in Niharika was obtained from the earliest sown crop.

No significant differences in seed yield were observed as a result of different N levels. Seed quality parameters, viz., seed weight, per cent germination and seed vigour, were also adversely affected by late sowing.

1.10.4 Seed Quality Testing and Enhancement in Medicinal Plants

Seed testing protocols were formulated in senna (Cassia angustifolia), isabgol (Plantago ovata) and muskdana (Abelmoschus moschatus). Dormancy class and type were identified in order to determine the requirements of pre- treatments and additives.

In sarpgandha, majority of seeds are empty with no embryos leading to very low seed germination. Therefore, a sorting technique was identified for separating the filled seeds of sarpgandha (with viable embryos) from empty seeds (with no embryos or aborted embryos) by floating the seeds in water or solvents. Floating (empty) seeds (about 80% by number) could be removed from the submerged seeds (which are filled and possess embryos) for getting higher germination (> 80%) of the seed lot, which emphasizes the importance of seed processing after seed harvesting.

1.10.5 Assessment of Seed Vigour

Seeds of onion and soybean are inherently poor storer species as they rapidly lose vigour and viability under ambient conditions. While standard germination test is a good indicator of seed germinability under favourable conditions, assessment of vigour is considered more reliable for determining the planting value of the seed even under less favourable as well as favourable growing conditions.

A two-year study with a large number of varieties revealed that among different methods of vigour estimation,

Effect of different sowing dates and nitrogen levels on seed yield of two varieties of isabgol (Plantago ovata)

N Sowing dates Mean

level November 2 November 17 December 3 yield (kg/ha) GI 2 Niharika GI 2 Niharika GI 2 Niharika (kg/ha) 0 748.3 520.0 536.7 623.3 401.7 403.3 538.9 45 735.0 433.3 596.7 575.0 366.7 315.0 503.6 90 635.0 461.7 403.3 671.7 388.3 368.3 488.1 Mean 706.1 471.7 512.2 623.3 385.6 362.2 510.2 CD at 5 %: N = 44.87, Sowing dates = 69.87, Varieties = 36.64, N x dates

= 77.27

Seed germination protocols for medicinal plants

Species Substrate Temperature 1^st Final Pre-treatments /

oC count count additives Cassia BP 25 or 30 6^th day 12^th day Pre-treatment with

angustifolia H₂SO₄ for 30

minutes or boiling water equal volume Plantago TP 20 4^th day 6^th day Pre-chill 24 - 48 h

ovata or GA₃ 250 ppm

co-applied Abelmoschus BP 25 or 30 7^th day 13^th day Pre-treatment with

moschatus H₂SO₄ for 5 minutes

or hot water equal volume

viz., speed of germination, seedling dry weight, EC of seed leachates, germination after accelerated ageing (AA) and controlled deterioration tests, volatile aldehyde (VA) trapping test and a new vigour test (NVT) developed by the Institute, the highest significant correlation with field emergence was obtained with AA test (0.602**), followed by EC of seed leachate (-0.588**) and VA (-0.417**) tests in soybean. In onion, the highest significant correlation with field emergence was obtained with AA test (0.731**), closely followed by CD (0.685**), EC of seed leachate (-0.677**) and NVT (0.662**).

The new vigour test (NVT) is based on the ability of seed to germinate under low oxygen availability and high levels of volatile aldehydes accumulated in a closed container (capped conical flask). The loss of seed vigour being associated with higher production and release of volatile aldehydes, the seed lots having low vigour are exposed to higher levels of such gases, which in turn, inhibit germination and seedling growth. The test is also effective in soybean, but in this case, seed coat integrity and solute leakage play a greater role.

1.10.6 Effect of Seed Priming on Capsicum Seedling Emergence and Vigour in Nursery

Seeds of capsicum cv. Calfornia Wonder were primed using osmoticum, salt and water, and were sown in well prepared nursery beds. Osmopriming (73.5%) and solid matrix priming (SMP) (72.2%) treatments were more effective than other treatments including control in improving seedling emergence. Maximum seedling fresh weight (636 mg/

seedling) and dry weight (76.8 mg/ seedling) were recorded in SMP treatment. Solid matrix primed seed also improved seedling length. Results indicated that solid matrix priming can be successfully used to improve emergence and vigour of capsicum seed.

Effect of seed priming on capsicum seedling emergence and vigour

Treatment Emergence Per seedling

(%) Fresh Dry Length

wt. (mg) wt. (mg) (cm)

Osmopriming 73.5a 545b 73.0ab 5.87b

Solid matrix priming 72.2a 636a 76.8a 6.96a

Halopriming 68.6b 552b 69.9b 6.64a

Hydropriming 66.2c 465c 51.6c 5.73b

Control 62.5d 320d 39.9d 4.64c

1.10.8 NMR Relaxation Studies during Water Imbibition in Microwave Treated Seeds of Fodder Legume Stylo seabrana

Hard seededness of Stylo seabrana seeds was reduced and germination percentage increased by treating them with 840-1260 watts/g seed of microwave energy. The improved germination of treated seeds was explained by NMR relaxation studies, which indicated early appearance of bound water (40 h prior to control) that helped in hydration of macromolecules needed for germination related activities.

1.10.9 Seed Production

At the Seed Production Unit of the Institute (Delhi) and at the Institute’s regional stations at Karnal, Pusa, Indore and Katrain, nucleus, breeder and IARI seeds of different varieties of cereals, pulses, oilseeds, vegetables and ornamental crops were produced during the year under strict quality control.

Apart from seed production, 28 rose saplings and 932 fruit plants were produced at the Seed Production Unit (Delhi).At the Regional Station, Karnal, about 4000 horticultural plants were produced.

1.10.7 Effect of Pre-sowing Seed Exposure to Static Magnetic Field on Growth of Maize Seedlings under Soil Moisture Stress

Maize var. Ganga Safed 2 raised from seeds exposed to static magnetic fields of 1000 Gauss for 2h and 2000 Gauss for 1h and subjected to soil moisture potentials of -0.2 MPa and -0.4 MPa for one month showed enhanced root characteristics like total root length, root surface area and root volume. This enabled the plants to maintain greater plant water status than the untreated plants, which resulted in improved plant growth in terms of leaf area and total plant weight.

Enhanced shoot growth of one month old magnetically treated plants of maize var. Ganga Safed 2 under soil water stress

Seed production (in tonnes)

Crop Nucleus seed Breeder seed IARI seed Total seed

Seed Production Unit (Delhi)

Cereals 0.5 28.61 185.21 (Included the 214.32

outreach programme seed)

Pulses 1.96 - 14.33(Included the 16.29

outreach programme seed)

Oilseeds - 1.16 3.52 4.68

Vegetable 4.3 (kg) 16.3 (kg) 1430 (kg) 1450.6 (kg)

Flowers 6 (kg) - 63.7 (kg) 69.7 (kg)

Regional Station, Indore (Breeder seed produced under farmers’ participatory programme)

Cereals - 203.00 - 203.00

Oilseed (Soybean) - 4.00 - 4.00

Fruit (Papaya) - 17 (kg) - 17 (kg)

Regional Station, Wellington (Breeder seed produced under farmers’ participatory programme)

Cereal - 10.00 - 10.00

Regional Station, Pusa

Fruit (Papaya) - 5.4 (kg) - 5.4 (kg)

Regional Station, Katrain

Vegetables - 0.722 2.897 3.619

Regional Station, Karnal

Cereals 3.39 101.48 244.90 349.77

Forage 0.12 2.10 1.97 4.19

Oilseeds 0.02 0.68 1.23 1.93

Pulses 0.09 4.00 7.43 11.52

Vegetables 0.39 4.41 0.72 5.52

Others - - 0.80 0.80

In document okf"kZd fjiksVZ - Annual Report 2007-2008 (Page 41-46)