Hybrid Paddy Seed Production Technology- AK Gupta, Ph.D

Location : Karimnagar, Kurnool, Warangal, Toopran, Shadnagar, Nizamabad, Miryalguda, Sattupally, Attur (T.N), Mysore (Karnataka)
Soil type : Preferably red soils, Light black soils. Saline soils & deep cotton soils are not preferred. If compulsory use Gypsum for Saline soils. There is a difference of 2 days in flowering between both the parents from red soil to black soil. In black soils - difference between flowering increases by 2 days
Season : Preferably Rabi (Post rainy or Dry season), Kharif (Wet season) normally results in low seed yields.
Days to flower : Andhra .Pradesh (Rabi/DS) Andhra Pradesh (Kharif/WS) Tamilnadu (Early Rabi) Mysore (WS/Kharif) Sowing Period :
Rabi season (DS) : 15th Nov (1st male) to 5th Dec . Sowings after 10th Dec results in low Yields.
Kharif Season (WS) : 25th May to 30th June. Kharif sowings are risky & normally results in low seed yields. Chances of grain deterioration & Poor germination..
Early Rabi (Attur -Tamilnadu) : 15th Sep to 15th October
Staggering : Differ for Hybrid patents
Note: Male parent is Photo & Thermosensitive, Male parent takes more number of days to flower particularly in late sowings after 10th Dec. Thus male flowering gets delayed by 5-8 days . Poor nicking results in poor seed set.
Seed Rate : Male Parent :3 kg & Female Parent 5 kg per acre (Note: Need to use more seed of male parent in order to increase plant population to get more pollen load).
Transplanting: Rabi & Early Rabi: Transplant male parent first when 2nd sown male seedlings are of 25-30 days old, followed by female parent.
Kharif (WS) : Transplant male parent first when 2nd sown male seedlings are of 30 days old. Give 4-5 days gap then transplant female parent when seedlings are of 22-25 days old.(If gap is more than 4-5 days between two transplantings, soil becomes hard to transplant. Transplanting in hard soil reduces root growth & prevents root penetration in the soil, which results poor growth of the plant.
GA-3:Spray 12gms (60 ppm) GA-3 at 5-10% flowering and 8 gms (40 ppm) at 35-40% flowering during evening hours. Late or too early spray give negative effect. Give 1-2 sprays (2gms of GA-3 per spray) only to male parent separately to increase plant height.
Supplementary Pollination : with stick is more effective. Need to engage minimum of 4 persons per acre. Supplementary pollination needs to be done 4-5 times during anthesis. That is normally between 10.30 a.m. to 12.30 p.m.
Physiological Maturity including tillers : Female Parent : 145 days in normally-may differ for hybrids parents
Days to harvest at 18%-20% moisture including bottom spikelets of tillers : Female Parent : 155-160 days(may vary for hybrids parents wise)
Average Yield per acre : Male parent 500-800 kg & Female Parent 600-800 kg
Water Stress Condition : Male parent advances in flowering
Key success factorsMore male plant population to get more pollen.Timely sowing & TransplantingHigh Crop management.Effective Supplementary pollinationEffective & efficient field monitoring.

HYBRID PADDY : GUIDELINES FOR TRIAL SEED PRODUCTION : AK Gupta, Ph.D

These guidelines have been provided to primarily help in successful hybrid rice seed production. Timely operations would help to raise the best crop with proper synchrony of male and female and high seed yield.
Seed Rate: For ¼ ac trail 1.25kg Female and 500g male has been issued, divide male in three equal parts to make three male sowings on different staggered dates.

SELECTION OF FIELD :
The selected fields should have fertile soil, assured irrigation and good drainage system.

NURSERY RAISING :
: ** Female and male nursery should be sown on separate seed beds so as to avoid any chances of mixture.

LAND PREPARATION, FERTILIZATION AND METHOD OF SOWING :
Nursery area should be well puddle (a week before sowing), levelled and kept weed free. It should have adequate water for irrigation and good drainage system.
Provide adequate fertilizer to nursery beds i.e for each 40 sq. metre area of nursery bed, provide 0.36 kg Urea, 0.36 kg DAP and 0.28 kg MOP at the time of sowing.
Soak @ 1 Kg. seed in 1.6 liters of water containing 2 gms of ceresan-wet for 8-10 hours. Pregerminate this wet treated seed by incubating in warm moist conditions for 36-48 hours or until germination.
Broadcast these pre-germinated seeds on drained beds at the rate of 1 Kg seed per 40 sq.metre. It is very important to sow the seed as mentioned above to get healthy seedlings. Thick sowing of seeds would lead to weaker seedlings .
Keep the nursery beds moist, for the first few days. Do not flood the beds. When the seedlings are about 1 inch high, keep the beds submerged in a shallow layer of water.
Top dress the seed beds with 0.28 kg Urea /40 sq. metre area, 10 days before transplanting. Seedlings will be ready for transplanting in about 35 days. Transplant male when 2nd male is 35 day old.
If the seedlings in the nursery show the yellowing to whitish of leaf tips, spray them three times with 0.5 - 1% ferrous sulphate solution 5 gm/ litre.

ISOLATION :

Distance isolation is the best isolation for raising the hybrid seed production plots. An isolation distance of 100 metres is recommended to obtain pure hybrid seed. This means that no other variety of rice should be grown in vicinity of 100 metres except the pollen parent. In cases, where somehow, distance isolation is not available, a minimum of 3-4 weeks time isolation is possible. Care should be taken that the other variety having time isolation should not flower within 3-4 weeks period of the hybrid seed production plot.
ROW RATIO : 2:6 Two rows of male : Six rows of female
ROW DIRECTION :Row direction should nearly be perpendicular to direction of the wind prevailing in the area at the time of flowering to promote out-pollination.
PLANTING PATTERN :
Transplant male seedlings in the main field 35 days after second sowing of male parent in paired rows 15 cm apart. Within a row, transplant single seedling of male nursery per hill in such a way that seedlings of three different ages may alternate each other systematically.
Next set of paired rows of male nursery should be transplanted leaving a gap of 135 cm with the help of planting board, for planting the female seedlings at a later date.
Continue transplanting paired set of male rows throughout the field, following the above pattern.
Keep all extra seedlings of male nursery in one corner of the field for gap filling.
Gap filling should be done within one week of transplanting in the male line after which all remaining male seedlings should be destroyed.
Start transplanting female line 35 days after sowing i.e. after planting the male lines. Six lines of female nursery are transplanted between 2 sets of rows in such a way, that outer rows of female line are 30 cm away from the male line, but each female line is 15 cm away from each other. The figure for transplanting pattern has been appended for your reference. In summary, the spacings would be as follows :
Among male rows 15 x 15 cm
Among female rows 15 x 15 cm
Between male and female rows 30 x 15 cm
FERTILIZERS SCHEDULE :- Avoid excessive use of nitrogenous fertilizer to check excessive vegetative growth. Following schedule is recommended (in kg/ha).
@ 36 N, 24 P2O5, 24 K2O kg/ acre)
Time of application DAP Urea MOP
(kg) (kg) (kg)
Basal at the time of transplanting 52 6 40
3 weeks after transplanting - 27 -
6 weeks after transplanting - 27 -
Apply 1/3rd nitrogen, whole of DAP and MOP at last puddling. Broadcast the remaining Nitrogen in 2 splits i.e., three weeks and six weeks after transplanting.
ROGUING :
In order to produce pure hybrid seed rouging must strictly be followed. In addition to strict isolation distance of 100 m, following additional points must be kept in mind while rouging :
TIME OF ROGUING:Early morning time is the best time for rouging. Care should be taken to complete this activity before start of anthesis so as to avoid any contamination. The rogue plants must be uprooted and destroyed. Normally the following kinds of plants are observed in the field:
MAINTAINER PLANTS : These plants have more or less similar appearance as the female plants but are 3-5 days earlier in flowering than the female line. Moreover these plants have yellow, plumpy and dehisent anthers compared to white, empty and shrivelled ones in the female.
OTHER OFF-TYPE PLANTS : Based on plant height, growth duration,spikelet number, shape and size, leaf colour and size and other morphological traits off-type plants can be identified and removed.
Note : Rouging should be undertaken from booting stage till the end of flowering.
GIBBRELIN APPLICATION AND SUPPLEMENTARY POLLINATION:
GA3 plays an important role in hybrid rice seed production. It helps in resulting better exertion of panicle from the leaf sheath thus better outpollination. GA3 spray should be done twice first at about 5-10% flowering and second one day after the first spraying Normally evening time is the best time for spraying GA3 when there are no dew drops on the crop. Effect of GA3 would be washed if it rains within 6 hours of spraying.
To prepare solution use 12 gm of GA3 for first spray and use 8 gm of GA3 for second spray per acre. Since GA3 is not soluble in water directly, dissolve 1 gm of GA3 in 5-10 ml methyl alcohol or rectified spirit and then add desired quantity of water to make the final solution. Normally 175-200 litres of water is sufficient to spray one acre crop. While spraying, care must be taken to spray uniformly .
SUPPLEMENTARY POLLINATION :
Shaking of male parent panicles by a long bamboo stick or rope pulling during anthesis (normally between 0900 hrs to 1200 hrs) period helps in spread of pollen grains widely and evenly. This helps in enhancing rate of outpollination and thus higher seed set on female panicles. It is advantagous to carry out supplementary pollination only during anthesis period. Supplementary pollination without anthesis is of no use.
Note : All sprays during crop flowering stage must be takenup only during evening hours.
HARVESTING :
MALE PARENT : Male rows should be harvested from ground level 3-4 days earlier than the female rows. After harvest, check each line thoroughly for any drop out panicles of male parent. Any negligence at this stage can cause admixtures in hybrid seed. All the harvested male rows must be stacked separately away from the threshing floor.
FEMALE PARENT: Before harvesting female rows, check thoroughly for offtypes and dropped out panicles of male parent and ensure their complete removal. Harvest the female rows and stack them near threshing floor which must be away from male stack.
THRESHING :
Ensure complete cleaning of threshing floor by thoroughly checking any drop-out seeds. Preferably use a new area for threshing female seed. Female parent should be threshed before male parent to avoid any admixtures.
Dry threshed seed in thin layers for 2-3 days. Delay in drying leads to deterioration of seed quality and germination.
Pack the dry seed in new gunny bags and label them lotwise before despatching to the company.

Standardization of hybrid seed production techniques

The present investigation was undertaken to standardize appropriate hybrid seed production techniques using two parental lines, Kalyanpur Sona (male) and PBIG-4 (Female) and assessment of different quality parameters. Hybrid seeds were produced by four different methods, viz., hand pollination, insect pollination under cage, isolation planting with natural pollination and without pollinator under cage. The evaluation was done during summer 2004 and 2005 for fifteen horticultural traits namely, days to 1st male and female flower, number of primary branches per plant, days to 1st harvest, main vine length, number of fruits/plant, average fruit weight, fruit length, fruit diameter, seed cavity, fruit weight/plant, number of seeds/fruit, weight of seeds/fruit, seed yield/plant and fruit setting percentage. In addition to this, a series of laboratory tests were also conducted involving eight genotypes, viz., PBIG-1, PBIG-2, PBIG-3, PBIG-4, PBIG-44, PBIG-56, Kalyanpur Sona and DVTG-1 to determine the effect of abiotic stresses (moisture and salt) and storage (storage container and time of storage) on seed quality parameters. Further, sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) was also performed on two parental lines and F1 hybrid seeds produced through different mechanisms. In field experiments, significant variation was noted for all the characters except days to 1st male and female flower, number of primary branches and seed cavity. Out of four different methods, insect pollinator under cage method was found superior for fruit characters like fruit length (19.50cm and 20cm), fruit diameter (4.96cm and 4.30cm), fruit weight (76.3g and 73.3g), number of fruits/plant (28.6 and 25.3), fruit yield/plant (1.96kg and 1.69kg), number of seeds/fruit (20.20 and 19.40), seed weight/fruit (3.25g and 3.09g), seed yield/plant (92.1g and 78.1g) and fruit setting percentage (84.0% and 85.33%). Appropriate pollination time period for maximum fruit setting was standardized and noticed that from 6-7.30 AM (78.96%) and 7.30-8.30 AM (75.89 %) were found best time interval for hybrid seed production thorough hand pollination. Under moisture stress and salt stress test, it was found that germination percent, seedling length and vigour index decreased significantly as level of stress increased. The genotypes, PBIG-2, PBIG-4, PBIG-56 and Kalyanpur Sona performed well at –10 bar water potential where as under in salt stress, at 700mM NaCl concentration the best genotypes were PBIG-2, PBIG-56, PBIG-1, and Kalyanpur Sona for germination per cent, seedling length and vigour index. In seed storage experiment, germination percent, seedling length and vigour index in all the genotypes decreased with duration of time, but alluminium foil storage and polybag storage were observed to be good to maintain germination percent (84.82% and 83.87%) seedling length (15.17 cm and 14.32 cm) and vigour index (1289.44 and 1202.75) even after 11 months of storage. For all the seed quality traits, the genotypes PBIG-2, Kalyanpur Sona, PBIG-56 and PBIG-1 performed best in both the years. A total of 17 bands were detected in two parental lines and the F1 hybrid. The parental lines and F1 hybrid could be distinguished on the basis of their banding pattern. But the banding pattern was observed to be similar for parental lines and F1 hybrid produced through different mechanisms.

Refinement of agro-technology for hybrid seed production and assessment of its purity :- AK GUPTA, Ph.D

The four sets of investigations were undertaken for two years to study (i) agro-management techniques for increasing hybrid seed yield in production plot, (ii) study the synchronization methods of flowering of hubris and its parental lines of hybrid, (iii) assessing the genetic purity of parental lines and hybrids using conventional and molecular approaches and (iv) discuss the potentional implications of above findings in hybrid seed production programme of the country. The material in first two sets comprised of A, B and R lines of hybrid Pant Sankar Dhan 3 and third and fourth sets consisted of (a) grow out test of four hybrid seed lots and, (b) SSR and STS maker analysis of 10 hybrid seed lots and their 13 parental lines. Sixteen agro-techniques studied had a combination of varying seed rates, seeding depths, N dosage and application methods in nursery and N dose and their application methods and population density in the main field. Data on days to 50% flowering, (DF), plant height (PH), tillers/hill (TN), panicles/hill (PN), panicle length (PL), spikelets/panicle (SP), per cent panicle exsertion (PPE), panicles/m2 (PMS), per cent seed set (PSS), 1000-seed weight (SW), seed yield/hill (SYH) and seed yield/m2 area (SYM) of the seed parent and DF, PH, TN, PN, PL, SYH and SYM for the pollen parent were recorded. Results from the pooled data revealed highly significant variances due to treatments for all the characters of A and R lines of the hybrid. Interaction effects between treatments and year on seedling growth parameters were significant for most of the traits of pollen parent only. Maximum TN were produced between 14 to 21 DAT which declined rapidly thereafter. The best agro management technique yielded 4.3 t/ha of hybrid seed and 7.8t/ha for restorer (male) parent in seed production plot. It involved lower seed rate (15 g/m2 area), deeper (5.0 cm) seeding and higher N (150 kg/ha) dose with three split applications in the nursery and high N (210 kg/ha) with four splits and transplanting two seedlings/hill in A/R production plot.
Seeding sequence of parental lines of Pant Sankar Dhan 3 for multiplication of A line (A/B) and hybrid seed production (A/R) was determined using three methods of synchronization. In growth duration difference (GDD) method, B and R lines are earlier on an average of three planting dates by 5 and 4 days with respect to their seed parent. Effective accumulated temperature (EAT) for flowering of A, B and R lines are 1477.53, 1397.13 and 1421.66oC. Leaf number (LN) for flowering of A, B and R lines are 16.50, 14.96 and 15.30, respectively. For synchronization, seeding of B and R lines is suggested when the A line attains LN of 1.54 and 1.2, respectively for A/B and A/R production. Study revealed greater consistency in flowering days in CMS line with LND method, as compared to other two methods. It suggests LND method to be more reliable across the planting dates followed by EAT and GDD to predict synchronization between parental lines of hybrids.
Grow out test identified the hybrids as well as the traits with maximum percentage off-type plants. Flowering was to be most useful trait during selection/evaluation of a hybrid and genotype for genetic purity. DNA markers RM 154, RM 164, RM 234, RM 258 and RM 519 displayed polymorphism over all 13 lines and nine hybrids studied and suggested them as referral marker for authentication, purity estimation and protection of hybrids. Within 13 parental (A, B and R) lines, only IR62829A revealed single off-type plants out of 25. The only hybrids confirming certification standards were Pant Sankar Dhan 1 (Syngenta), Pant Sankar Dhan 3 and Sahyadri. Study suggests use of appropriately chosen single microsatellite marker to estimate the genetic purity in hybrid rice. Correlation coefficient between GOT and DNA markers (0.89) highly significant and positive and suggests molecular techniques to substitute the conventional GOT which is more land, labour, money and time consuming.

Genetic investigation on methods of synchronization in flowering for hybrid and parental lines seed production across planting dates :- AK GUPTA, Ph.D

Synchronization of flowering between parental lines assumes much greater significance to ensure higher yields in seed production plots. Due to genotype x environment interaction, duration in 50 per cent flowering of the parental lines differ over locations/planting times. The present study determines the seeding sequences of parental lines of CMS based hybrid Pant Sankar Dhan 3 for multiplication of A, female parent (A/B) and hybrid (A/R) under three planting dates using three methods of synchronization viz, differences in growth duration (GD), leaf number (LN) and effective accumulated temperature (EAT) of the lines involved. ANOVA revealed significant mean squares for genotypes and sowing dates for all the lines and genotypes × sowing date interaction is significant only in respect of EAT. Result indicated that in (GD) method, B and R lines flowered earlier on an average of three planting dates by 4 and 3 days with respect to corresponding seed parent. Respective values of EAT in respect of flowering of A, B and R lines are 1477.53, 1397.13 and 1421.66ºC and leaf numbers 16.50, 14.96 and 15.30. For synchronization, seeding of B and R lines is suggested when the A line attains LN of 1.54 and 1.20, respectively for A/B and A/R production. Study also revealed greater consistency in flowering days in CMS line with LN method, as compared to other two methods. It suggests LN method to be more reliable across planting dates followed by EAT and GD to predict synchronization between parental lines of hybrids
Key words: Hybrid rice, Synchronization, Growth duration, Leaf number, EAT