15AGRITECHCAT3 - Improved crop breeding programmes through advanced Pollination Control Bag materials technology

Developing new crop varieties requires controlled pollination between parent plants with the desired characteristics. A good way of controlling this process is to carry it out within an isolated environment using a pollination control bag (PCB). These bags need to allow light penetration, control humidity and allow air circulation whilst preventing other pollen from entering the bag. Although, current PCBs conventionally made from a paper-based material are relatively cheap, they are single use and have a tendency to rip easily and are prone to slug infestation, which means that the environment is no longer sufficiently isolated to ensure a controlled cross pollination. Superior materials for PCBs that overcome these challenges
are therefore required. The project will investigate the technical and commercial feasibility of developing an innovative pollination control bag to improve crop breeding programmes used for three important agricultural crops: sugar beet, wheat and Miscanthus. A range of materials (woven and nonwoven), fibre technologies and techniques will be investigated and trialled with academic and commercial breeders with the aim of developing the next generation of pollination control bags to improve breeding outcomes, reduce losses caused by poor temperature and humidity control within the bag, and increase seed yield.

Crop breeding is achieved through the selective and controlled breeding of two parent lines, aiming for improved yields, product quality or disease & pest resistance. Getting new varieties to market quicker is critical to the success of commercial seed producers. Pollination Control Bags (PCB) are commonly used to control pollination, preventing ingress of foreign pollen and contamination. Pollen is either puffed into the bag or pollinator insects are put inside the PCB to ensure the plants inside cross with each other. Due to heavy demands for space, high operating cost of glasshouses used for crossing, & large number of crosses undertaken, bagging helps to achieve rapid throughput of populations. Each individual genotype is labelled and a pollen-proof bag is placed over the heads and secured at the stem.

The pore size and type of fabric used are extremely important in any controlled pollination experiment. Various materials, including polyester, polyethylene, paper and glassine are commonly used for greenhouse breeding. Paper bags are widely used for sorghum, millet and maize breeding worldwide but are single use only, tend to rip easily and are prone to slug damage, resulting in an insufficienty isolated environment. Plastic, cellulose & nylon are currently used for PCBs in cereals and some insect pollinated crops. However, current PCB's or sleeves create an artificial microclimate which can be detrimental to the plant, so a substantial proportion of plants are usually lost to disease pressure and/or fail to gain sufficient seed for the next stage of testing. The technical output of the project will be a commercially viable, highly specialised PCB material building on prior knowledge of material engineering techniques to ensure manufacturability and hence commercial viability of the resulting product. This will improve pollination control and increase the efficiency of crop breeding programmes, thereby accelerating the development of new varieties.

The project will result in a novel PCB material specification and PCB design. Data and evidence from material testing under greenhouse conditions to demonstrate feasibility for sugarbeet, Miscanthus and wheat will also be generated. This demonstration of technical feasibility will then require techno-economic assessment, including an assessment of potential manufacturing options and scale up prior to commercialization (approximately 12 months from project end). A fit-for-purpose PCB will significantly improve crop breeding programme efficiency, reduce costs for the breeders and also accelerate the rate at which new commercial crop varieties with improved yields, disease or pest resistance, and higher crop quality, can be discovered and brought to market. Improved seed set and germination rate could therefore decrease the number of crosses needed (perhaps by 50%), and will also allow scale-up of trialling progeny, thereby accelerating the development of new varieties with useful characteristics (e.g. drought tolerance, suitability for local soil conditions, pest resistance, increased yield) to meet ever increasing global demands for food and feedstocks to support a growing bioeconomy.
The agricultural sector and farmers specifically, will be the direct beneficiaries of these advances in plant breeding. Increased financial returns and more confidence in crop choice will come from the ability to choose from a wider range of crop varieties than is available at present. Improved plant breeding will be of benefit to society at large via stable crop prices and improved UK food security (in relation to sugar beet and wheat).
The manufacturers of PCBs will benefit from the success of this project via an increased market share. Whilst this project is focused on 3 key crops (sugar beet, wheat and Miscanthus), optimizing PCBs for other crops may also be possible through future collaborative R&D between the partners.