Maize (Zea mays L.) productivity in the middle hills of Nepal has either been static or declining over the last two decades. As a prerequisite for designing a participatory maize improvement programme for the middle hills that could reverse these declining yields, local knowledge and practice were investigated and combined with micro-meteorological measurements, at three sites each with more than 25 participating fanners. Acquisition of local knowledge widened understanding of the existing maize production systems. Farmers possess a vast and sophisticated knowledge from which an explicit understanding of their maize variety selection criteria was derived using a knowledge-based systems approach. Some issues articulated by farmers were new to researchers in Nepal, including their perception that; some traditional maize varieties with a broad genetic base were tolerant of attack by stored grain pests; some were tolerant of
drought because of their deep rooting systems; and tree shade affects disease development.
The variability of the bari land terraces with respect to maize cultivation practices and micro-meteorological parameters experienced by maize crops were assessed in on-farm observation trials. These both varied between sites and between farms within sites. There was a great variation amongst farmers in the amount of inputs they used. The use of very high maize seed rates was part of a risk management strategy while also providing a source of livestock fodder from thinned plants.
Photosynthetically active radiation (PAR) incident upon maize was below 700 µmo! m-2·s-1 under on-farm conditions in 1999 and 788 ~tmol m-2 s-1 in the open but 455 µmol m-2 s-1 under artificial shade in an on-station trial in 2000 of which about half was intercepted by the maize crop. These values are far below the light saturation level of 1500 ~Lmol m-2 s-1 for maize.
Farm trees and artificial shade had significant negative effects on maize yield (36% and 43% reduction respectively). Reduction in plant height and leaf size due to shade was about 7% and 10% respectively. Root length density (RLD) was lower under shade for all varieties and the vertical distribution upwardly displaced. Varietal differences suggest that the prospects for breeding new varieties with deeper rooting is high, which could improve lodging and drought and nutrient stress tolerance. Both Participatory Variety Selection (PVS) and Participatory Plant Breeding (PPB) were carried out simultaneously. Six new maize varieties were compared with
locals. Farmer managed participatory research (F AMP AR) trials, where farmers grew a subset of new varieties next to their local were combined with varietal demonstration trials of all the varieties at different locations. One variety, Population-22, despite its late maturity was liked by farmers for disease tolerance, higher yield potential, its large, white-coloured grains and its stay green characteristics. Statistical analysis of grain yield confirmed farmers' preference for Population-22, since this out-yielded others. Arun-1 was the lowest yielder; but farmers have been adopting it because it is short duration and
so provides early food availability. Revolving seed multiplication schemes for these varieties have been initiated by farmers, which may guarantee the sustainability of the programme.
As a result of the PPB programme, four composites have been generated using farmers' expertise so as to offer choices of new varieties back to them as early as
possible, thus increasing the genetic diversity they are able to evaluate and utilise. These materials are ready to be evaluated in multi-location regional and national trials. This study has clearly demonstrated that understanding farmers' maize selection criteria and involving them in the variety selection process can improve the efficiency of research and variety uptake by farmers. The prospects of increasing maize production
appears high because farmers are already spontaneously adopting the new varieties that they have chosen. This could help tackle the critical rural food deficit problem in the middle hills of Nepal. However, the present centralised policy of the national agricultural research system, is not conducive to experimentation with farmers, and institutional change is required to increase the functional participation of farmers, researchers and development workers, if participatory maize research is to be effective and sustainable.