Setting of pods on male sterile plants in insect proof nets

CMS lines were grown inside the insect proof net cage of about 40X40 meter size along with some fertile restorer lines for production of hybrid by hand pollination. We have observed that there are some plants of CMS genotypes which have good pod bearing (exceeding 50 pods per plant) without hand pollination. They are confirmed to the genetic purity in respect of male sterility and other traits of the variety. Normally, we don't expect such setting inside the net and it was so in majority of the plants. We are now bothered to have the reasoning for such exception. We think that following may be the possibilities:

1. The plant is responding to the pollination through miniature insects like thripes which are abundant in pigeonpea.
2. The pod setting may be developed automatically.
3. Wind pollination from the neighboring fertile plants.

Readers are invited to share their experiences with the evidential references from the literature.

Prepare against unseasonal rains to protect the produce from our fields

How far to continue under the threat of unseasonal rains?

My Dear Farmers,

During Kharif 2010, there was very harsh experience with many farmers whose standing matured crops of Mung, Udid, Soybean,Sorghum, Bajra, etc. were damaged and our friends succumb to the enormous losses due long wet spell. We may take some lesson from it and get prepared for such unseasonal rains to protect the produce from our standing crops like TUR (Arahar), cotton and other kharif or rabi crops. We can take some measures to cut the losses from such rains at maturity.

What can be done? 

• Have you seen the shop vendors in weekly bazaar sitting with their goods for sale in a small tent of canvas sheets hanged on three bamboo sticks (two vertical and one horizontal), and stretched at four corners tied on the iron nails or bamboo pegs? Definitely, my farmer friends have seen it. 

Temporary cover

• How the run off water coming down from the tent is not allowed to damage his goods? Very simple. The platform to keep the goods is a raised bed by 3 to 5 inches (15 to 25 cm) simply using small stones supplemented by some soil. The furrow is prepared at borders by digging with a small crowbar or by a hard iron nail and the soil coming out of it is put on the platform.  

• Such little conscious efforts and small investment can save large amount of losses. Why not to take this model on our farm where we are growing our crops for years together? For an individual it is very easy and feasible.

•  If you are convinced, you can decide following things according to your choice and investment capacity. It can be temporary portable unit.Location of the platform required for the crop harvest before threshing based on convenience and labor cost for transport,

• Dimensions of the platform needed for the crop
• The field may be divided in suitable grids, each of which may be of about an acre area, provided with the space for platform.
• Materials to be used for the platform and tent i.e quality of tarpaulin or simple plastic paper sheets,
• Bamboo or iron pipes,
• Height of the platform and 
• Materials to be used for raising it.
 



Platform

• If you decide to have good quality tarpaulin on large scale, a pool can be developed by a group of 10 or more farmers. Contribution of small amount from each of them will make it big pool of >10 tarpaulins. There is every possibility that every one of the group members may not require the tarpaulin at the same time. We can formulate certain rules for custom hiring the items from such pool for members and non-members. It may be further developed into a private entrepreneurship by few rural youths.
  
  
• May I add here that Dr Panjabrao Deshmukh Krishi Vidyapeeth, Akola has demonstrated a portable emergency cover for the threshing floor. It is round in shape. It can be seen at the Post Harvest Technology Museum at this university's Post Harvest Scheme.

Feasibility of heterosis breeding in pigeonpea

Scientific expertise and knowledge developed in the world is now easily accessible. But how quickly, efficiently and effectively one can handle the problem will depend on the strategy planned. Development of a particular approach in crop improvement is based on the convenience. The convenience is decided by various considerations such as the status of the crop improvement work, available varieties and germplasm in relation to the target. These points make one to enter into either technically easy or complicated strategies. Other considerations are about the resources in terms of manpower, finance, field and laboratory facilities available at the disposal of a plant breeder.

Pigeonpea improvement in early ages started with limited resources. Selection from landraces were tried by the breeders. Later it was emphasized to incorporate resistance to major diseases like Fusarium wilt and sterility mosaic. Unfortunately the pigeonpea improvement was restricted to conventional breeding until last few decades, may be due to limitations on resources available and could not achieve gains in productivity potential (Saxena, 2002) to cope up with increasing demand. In recent years increasing demand for pulses on one hand and limited availability on the other, invited attention of many countries as the crop for export to Indian subcontinent. It has now greater value than any time in past and invites research policies to have new non-conventional approaches like heterosis breeding.

Pigeonpea has been considered technically suitable for heterosis breeding due to predominance of non-additive genetic variance for the traits like grain yield and other important yield components (Reddy et al. 1981, Sidhu and Sandhu, 1981; Saxena and Sharma, 1990). Germplasm presents wide rage of genetic diversity. Abundant natural out pollination (Saxena et al. 1990) can be utilized to avoid tedius hand pollination. The need of male sterility to avoid mechanical emasculation has been fulfilled through discovery of genetic male sterility  (GMS)(Reddy et al. 1978 and Wallis et al. 1981, Wanjari et al. 1995) and CGMS (Tikka et al. 1998; Wanjari et al., 1999 and Saxena et al.,2003). These points favour commercial seed production of F₁ hybrids in pigeonpea, on the basis of which F₁ hybrid breeding using GMS has been attempted successfully to develop six hybrids for cultivation in India (IIPR, 2002, Saxena, 2002). However they faced the problems in commercial seed production. The pigeonpea breeders in India are now trying hybrid pigeonpea breeding on the CGMS systems based on the sterile cytoplasm from Cajanus scaraboides and C. cajanifolius.

Prospective in hybrid technology:

Saxena (2002) opined that the experiences with genetic male sterility based hybrid technology in the past 25 years has conclusively demonstrated that the exploitation of hybrid vigour is feasible if the seed production difficulties are addressed adequately. The male sterility has been now diversified in indeterminate good agronomic bases in early as well as mid-late or late group of pigeonpea and more than two dozens of male sterile lines with better potential of seed yield are available. These can be successfully utilized to have more productive hybrids.

In Central and South India, large proportion of the area is under medium duration pigeonpea under various intercropping system, where lower seed rate of 1 to 3 kg ha^-1 is used. This is one of the favourable points for the promotion of hybrid pigeonpea. AKPH-2022 has been the first medium duration hybrid released from Dr.Panjabrao Deshmukh Krishi Vidyapeeth, Akola which may have a better prospects under such situations more particularly in Maharashtra, Andhra Pradesh and Karnataka.

A package of GMS based technology for hybrid pigeonpea seed production has been developed through various considerations to improve the seed yield (Vishwa Dhar et al. 2002). It has been successfully demonstrated on the farmers field and has found to be acceptable to the seed growers. Further efforts to identify large number of morphological seedling marker traits (Patil et al. 1998) and to establish linkage of few of them with the genetic male sterility are in progress (Wanjari, 2002). It will facilitate rouging fertile segregants in early seedling stage.

Development of stable cytoplalsmic male sterility (Tikka et al. 1998; Wanjari et al., 1999 and Saxena et al.,2003) and further efforts to establish restorers (Tikka et al. 1998; Patel, 2001; Saxena, 2002) opened new avenue to work on hybrid pigeonpea. Chavan et al. (2004) established good number of fertility restorers for the CMS based on C.scrabaeoides. Wanjari and Patel (2003) reported few restorers able to produce hybrids which can set autogamms pod setting. Rigorous efforts will, however, be needed to purify the parental lines and to develop the hybrids based of A-B-R system of cytoplasmic genetic male sterility. 

Let us hope for better hybrids in near future.

PRODUCTION TECHNOLOGY FOR RABI PULSES UNDER DRYLAND AGRICULTURE

In India important rabi pulses are chickpea, lentil, lathyrus, mungbean, urdbean, fababean etc. They are very much location specific depending on the dietary preference of the particular area or region. Chickpea occupied maximum area of rabi pulses (8.4 lakh ha) producing 6.68 lakh tonnes, during 1998-99. The area and production statistics in India for rabi pulses in summarized in Table 1.

The productivity of rabi pulses is very much dependent on the duration of winter. Long winter is one of the reason to have better productivity in northern states than those in Central and Southern India. Under dry land agriculture the rabi crops are more dependent on nature for their moisture requirement; which is decided by climatic factor like rainfall, sunshine hours, humidity, temperature, rate of open pan evaporation etc. In peninsular India, the winter is not very cool and the minimum temperature below 15^oC is for very limited period. Moreover, day temperature shoots up above 35^oC much earlier (in February or so) in Southern part as compared to North Indian States. Hence, the varietal requirement varies in different states. In north, long duration varieties (above 135 days maturity) can do well, while in Centre and South short duration varieties of 90 to 110 days are more preferable. The varieties of major rabi pulses for different states are listed in Table 2.

Land requirement : As the dry land crops are dependant on residual soil moisture without irrigation, the soils should have excellent water holding capacity with better drainage and rich in organic carbon. Traditionally rabi lands were very much reserved by keeping them fallow in kharif following frequent tillage through harrowing which help water conservation and weed control. However, now a days short duration kharif crops maturing before September end or early October (e.g. mung, udid soybean) are followed by rabi pulses. Under such circumstances, it is very necessary that the kharif crop is weed free with better mulching for soil moisture conservation. Immediately after harvest of kharif crop, it is necessary to have harrowing to have better pulverized seed bed without much loss of soil moisture for rabi pulses.

Sowing : Sowing of rabi pulses under dry land condition should synchronise better soil moisture availability. For this reason it is sown immediately after the land preparation (after harvest of short duration kharif crops. The optimum sowing time, seed rate, spacing for various rabi pulses are given in Table 3. They are however adjusted as per the soils and climates of different regions and states. In North-India prevailing cool, humid weather in November, permit the sowing of pulses as late as November end. However, in Central & South India dry land rabi sowing is restricted earlier by mid October.

Care to maintain optimum plant stand:

a) Check germination percentage and seed index of the seed available for sowing. Adjust the seed rate on germination and seed index, to maintain optimum plant stand given in Table 3.

b) Seed treatment with fungicide (e.g. thiram) at the rate of 3 g per kg seed should be undertaken to avoid early seedling mortality. Now a days antogonist fungi viz., Trichoderma herzianum or T.viridi is found effective to control the early seedling mortality due to Rhizoctonia, Sclerotium or Fusarium. The culture of T.harzianum or T.viridi is now available and its seed treatment @ 5g/kg seed is equally effective to the fungicidal seed treatment. Use of carboxy-methyl-cellulose (CMC) @ 1g/kg seed as an adhesive, makes the treatment more effective.

c) Levelled land with uniform steady slope and providing good drainage at prepara tory tillage avoids water logging due to untimely rains. It is one of the major factor to cause seedling mortality uncontrollable even by the fungicidal or antagonist’s seed treatment.

d) Uniform drilling preferably through mechanical seeddrill ensures optimum spacing and plant stand.

e) Timely weed control to keep the field weed free at least for 45 to 55 days from sowing ensures the better plant growth and plant population per unit area.

Interculture operations: These are dependent on the soil type and weed infestation. The basic aims of interculture in dryland rabi pulses are the moisture conservation and weed control. It is therefore necessary to avoid hard crust of soil surface due to untimely rains and soil cracks due to dry and hot weather during the period upto 45 days from sowing. Later the well developed crop canopy take care of both the factors i.e. moisture conservation and weed control.

Plant protection : Pod borer (Helicoverpa armigera) is a major pest of chickpea and also of other rabi pulses. Integrated management approach against the pest is necessary. It involve the management of insects to the lower level of infestation which does not cause economic damage to the crop, by using different practices, including cultural mechanical, biological and use of biopesticides ultimately reducing the use of chemical pesticides to the minimum possible extent.

Protective irrigation : Whenever possible under prolonged drought, protective irrigation to the rabi crops is very beneficial. It has been observed that a single irrigation at flowering or pod development (whenever water stress prevails), improves the productivity by 30 per cent, while two irrigations (at both these stages) gives 52% yield advantage.

Harvesting, threshing and storage: Timely harvest of the crop to avoid shattering losses, need not be stressed. The produce after threshing should be thoroughly dried to ensure seed moisture below 10% and stored at dry place. The produce should be well protected against bruchids.