The promotion of agroforestry specifically industry- based agroforestry has exhibited wide range of challenges and constraints from the entire Production to Consumption System. Among the various challenges and constraints that existed in the agroforestry system the following are the most significant challenges which detract the attraction of agroforestry promotion and development (Parthiban et al., 2016).

Barring few exceptions, most plantation programmes established in the country deploys seed sources from unimproved genetic resources resulted in uncertain productivity and erratic wood quality. This resulted in uncertain and poor yield which act as a major barrier.

It has been estimated and also reported that the plantations established through unknown and unimproved genetic resources has exhibited a lowest productivity level of <10m3/ha/annum. This low productivity is a major challenge for the commercial viability of agroforestry systems.

The absence of improved genetic resources directly correlates with non-availability of quality planting materials. Most seedlings produced and deployed in operational plantation programme are from uncertified open nurseries without any genetic evaluation. These unimproved seed sources-based seedlings exhibited wide range of success and failures and limit the agroforestry developmental activities

Most industries use only one or two prioritized species amenable for the respective industrial utilization. Again, these species are predominantly exotic in nature and witnessed specific adaptability and acceptability. India is housed with wide range of indigenous species which are fast growing and accredited with excellent wood properties amenable for multifarious industrial utility. The inventory and utilization of these species is a major challenge for want of suitable and organized tree improvement programme.

The existing plantations established through unimproved genetic resources exhibited wide range of wood quality in terms of physical, chemical, mechanical, anatomical and other thermo-chemical properties. This besides, the form, structure, bark content, brittleness, incidence of post-harvest pest and disease, etc. also play a significant role in varying wood quality and pronounced as a significant barrier.

Another major challenge that limits and detracts the attraction of industrial agroforestry development in the country is the long rotation nature of tree component. Till the recent past, most plantations are long rotation and the growers have to wait for several years to reap the benefits from agroforestry. Since, most farm holdings in the country are of small size, the farmers depend predominantly on regular income from the agricultural activities. The translational towards agroforestry is highly recalcitrant which is a most significant challenge.

The above flagged issues are the major challenges and constraints that exists in the operational industrial agroforestry development programme which underscored the need for deployment of improved genetic resources through systematic tree breeding and improvement programme.

India is one of the robust producers and consumers of wood and wood products. Today, the country’s demand for wood and non-wood products is increasing at an alarming rate. It is estimated that the country would need over 700 million m3 to meet the raw material requirement of the organized sectors of wood-based industries (>152 million m3), unorganized sectors of industries (>150 million m3) and for energy requirement of domestic and industrial purpose (400 million m3) (FAO, 2009; Parthiban et al., 2021).

Several strategies are developed and implemented by government sectors, wood-based industries and other public and private players towards agroforestry promotional development but the achievement in this front is dismally modest. This is primarily due to non- availability of improved genetic resources and the associated quality seedling production, low productivity, long rotation and absence of alternate genetic resources. Hence, organized tree breeding and improvement received potential attention and attraction towards resolving the issues flagged above.

Among 28 states and eight Union Territories in the country, the potential of state of Tamil Nadu towards industry-based agroforestry is very significant due to the existence of wide range of wood-based industries like timber, ply and panel, pulp and paper, match splints, packing case, energy and other NTFP industries. It has been estimated that the state of Tamil Nadu needs over 70 lakh tonnes of raw material requirement to meet the organized sector of industries like timber (>30 lakh tonnes/annum), pulp & paper (17.5 lakh tonnes/annum), ply and panel (>10 lakh tonnes/annum), match splints (5 lakh tonnes/annum) and packing cases (>2.5 lakh tonnes/annum). This, besides the state would need over 100 lakh tonnes for biomass utility to cater to the raw material requirement of biomass power plants, co- generation plants, co-firing and other industrial energy utility (Parthiban et al., 2022)

Besides the existing demand, the state also attracting new wood-based industries like particle board, MDF, biofuel industries, furniture park, etc., which may require another 10 lakh tonnes per annum from the year 2025 onwards. Such a massive wood requirement for the state cannot be met from the existing forest due to legal restrictions and agroforests with varying wood productivity. All these developments have extended a greater scope and need for organized tree improvement programme in wide range of species to develop improved genetic resources, High Yielding Short Rotation (HYSR) clones and other speciality varieties.

Tree improvement programme incorporated with the deployment of clonal technology is very essential to develop short duration varieties and ensure the availability of QPM. Above all, inventorization, characterization and evaluation of indigenous species amenable for industrial utility, increased productivity and short harvesting period extend a greater scope for organized tree improvement programme. Accordingly, a systematic and organized tree improvement programme has been conceived and implemented in Tamil Nadu which resulted in successful varietal development and the entire process is discussed below

As indicated earlier, the state of Tamil Nadu is housed with wide range of wood, non-wood and other value addition industries and extends a greater scope of promotion of agroforestry both for industrial and commercial importance. The state of Tamil Nadu has seven agro-climatic zones and represents wide range of agro ecosystem amenable for cultivation of diversified agroforestry species. Above all, the people in the state of Tamil Nadu traditionally incorporates tree components in the farm settings through agroforestry, farm forestry, bund planting, sporadic planting, wind breaks, etc. Considering the demand that exists in the state coupled with assessing the existing land use and capability system followed by discussions and consultations with farmers and members of Consortium of Industrial Agroforestry, 30 tree species were identified and prioritized for incorporation in agroforestry promotion and developmental activities. The species prioritized and incorporated are furnished below.

FCRI, TNAU has developed a systematic and

organized breeding programme and implemented during the last three decades. However, after 2004 the breeding programme has been revisited and moderated deploying the current needs and technological advancements. The traditional tree breeding approaches like provenances seed sources and progeny evaluation has been the backbone of forest genetic resources assessment and formed as a base population for development of advanced clones and hybrids (Mitra, 2000). Though, 30 species have been identified for incorporation in the state of Tamil Nadu; based on demand from the stakeholders and the increased attention towards agroforestry, over 15 different tree species have been intensively deployed in organized and systematic tree breeding improvement programme. The general plan and tree breeding approach followed for most industry-based tree species are depicted in the figure 1.

The organized and systematic tree breeding programmes carried out over two decades have resulted in development of wide range of genetic resources amenable for industrial agroforestry with improvement in productivity and wood quality. The genetic resources were deployed and evaluated for the full rotation or harvesting period and based on the productivity and acceptable wood quality (industry specific/product specific). These clones are released through the State Variety Release Committee (SVRC) for adoption by farmers and other stakeholders. The clones so far released through the SVRC are presented in Table 1 along with yield and quality parameters.

Similarly, wide range of improved genetic resources amenable for multifunctional industrial utility are developed and are currently at pre-release stage. These clones are also demonstrated and deployed in various out-grower schemes. The major clones and improved genetic resources under pre-release stage are furnished in table 2 along with yield and quality parameters. The developed genetic resources predominantly in the form of clones are deployed in organized and consortium mode industrial agroforestry promotional programme (Figure 2).

Most of the tree breeding and improvement programme are extensively supported by wide range of industries like timber, ply and panel, pulp and paper, match splints, energy and NTFPs either directly or through the consortium. A suitable MoA was executed between TNAU and wood-based industries for a systematic development of industry specific varieties and the associated expansion activities through contract tree farming. This has extended continued research and development mechanism leading to development of

improved genetic resources and the associated High Yielding Short Rotation clones accredited with improved wood quality (Parthiban et al., 2019)

TNAU has conceived a value chain model on industrial agroforestry in 2005 and implemented in Tamil Nadu very systematically from 2008 onwards in association with wide range of wood-based industries to resolve various challenges and constraints that exist in operational agroforestry developmental activities. The major innovations are technological, organizational and marketing interventions through a consortium approach (Parthiban et al., 2021). An institutional mechanism called Consortium of Industrial Agroforestry has been established to link the entire production to consumption processes through technological supported mechanism. The improved genetic resources and the associated clones developed are linked through industry based out-grower’s schemes towards establishment of genetically improved industrial agroforestry plantations. The last ten years of technology leveraged agroforestry development has witnessed establishment of over 80,000 ha of organized and horizontally expanded plantations incorporating improved genetic resources of timber, ply and panel, pulp and paper, energy and NTFPs in association with respective stakeholders (Parthiban et al., 2022).

Some of the released clones in Casuarina and Melia are licensed to consortium member nurseries and incubated nurseries which resulted in expansion of improved genetic resources based industrial agroforestry development. The clonal licensing also extended royalty to the institute which has been judicially incorporated for all tree breeding and improvement activities on a sustained basis