Breeder Q&A: All about basil

Features - 2022 Produce EXPANSION GUIDE

A basil breeder and Ph.D. student at Rutgers University discusses one of controlled environment agriculture’s most crucial crops.

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March 21, 2022

photos courtesy of Lara Brindisi

As popular as basil is with consumers, and given its economic importance to our industry, this culinary herb has yet to benefit from the intensive research treatment enjoyed by crops such as corn, wheat and soy.

It’s also no secret that the pipeline of new degreed or experienced talent simply isn’t flowing as freely as it did in years past. Recruiting new talent who have either the credentials or experience you need for your growing operation is only getting tougher.

So, I decided to hit two birds with one stone in this month’s column and introduce you to my ASHS Mentee, Lara Brindisi, a Ph.D. student at Rutgers University, and share one of our conversations. She is a basil breeder studying how to make basil that can better adapt to climate change, diseases and other abiotic and biotic stresses.

I’ve been working with Brindisi as a mentor to develop her professional goals as she works to finish her Ph.D. I’ve also gotten to learn a bit more about her fascinating basil research along the way.

Leslie Halleck (LH): Before we get into your background and the nitty gritty of your research, what applications from your research do you feel would be useful to growing basil under glass or in controlled environments?

Lara Brindisi (LB): My lab works directly with growers, both outdoor and indoor, to improve basil. New Jersey has a large acreage of outdoor basil production, but also several indoor controlled environment, vertical farming and glasshouse production systems. Personally, my work with the indoor growers in and outside of New Jersey has been on observing the changes in plant chemistry and nutrition and working with the Tepper lab to observe the changes in human sensory perception in response to altering the environment.

LH: Wait, human sensory perception?

LB: It’s very useful to understand how the environment changes aromas, flavors and the underlying chemistry of plants, because then growers can change the lighting or fertilizer regime, for instance, to drive basil to produce a more powerful and/or desirable aroma and increase their market potential.

LH: OK, that’s cool … What new or interesting developments are you seeing emerge from your basil research?

LB: We have made a ton of progress in a relatively short period of time. We recently sequenced a reference genome, for instance, and this will help us and other labs learn so much more about the genetics, which we can apply directly to improving basil varieties. I am also working on CRISPR/Cas9 editing for basil, which is an exciting technique to learn as it has an immense amount of potential for helping crops adapt to climate and disease.

LH: What’s new and exciting on the horizon for food producers/basil growers you want to make sure readers know about?

LB: The Simon lab is working on improving downy mildew resistance in basil without losing key aroma and visual attributes. Keep an eye out for improved DMR (Downey Mildew Resistant) sweet Italian basils and new Thai basil and lemon basil.

LH: Oh, that’s exciting, as downy mildew is such a significant problem for the industry these days. There are already several cultivars that have been released through your program (readers can find those here: bit.ly/BasilRutgers). I know you are also working on chilling tolerance in basil, which could increase its field production range, as well as potentially reduce input costs under glass. I’m a bit of a basil junkie myself. What is your favorite basil to grow and why?

LB: I’m growing at least two varieties at any given time. I grow ‘Rutgers Obsession-DMR’ for Italian- and American-style dishes. It’s my favorite of the Rutgers downy mildew resistant varieties with a floral sweet basil aroma. Sometimes I also grow a traditional Genovese variety for these dishes, but it doesn’t always make it if it gets downy mildew. For Asian-style dishes, I grow Thai basil like ‘Queenette’. We’re currently working on improving Thai basils for downy mildew resistance as well.

LH: Great to hear. So, what got you interested in the research program at Rutgers and what specifically attracted you to the research on basil?

LB: I initially joined the Ph.D. program in Plant Biology at Rutgers University because the Simon lab offered a unique opportunity to intersect all my deeply seeded passions (pun intended) including sustainable agriculture, medicinal chemistry and international development. I spent the first few years of my program working on the chemistry and nutrition of African indigenous vegetables and vertically farmed baby leafy greens. However, in that time, I learned so much more about the field of genetics through my teaching assignment and my courses that I decided to transition my work towards plant breeding and genomics and our basil breeding program offered a much better opportunity to learn those skills. Plus, I can’t deny the Italian heritage that loves sprinkling basil in every meal.

LH: I could talk basil with you all day, but we only have so much space and time to do so. To wrap up, are there any thoughts about your work or the impact you hope to make?

LB: Plant breeding has been a historically male-dominated discipline, but we are seeing a flux of women enter the field (myself included). I’m excited to see how my contemporaries and I transform the space over the next 10, 20, 30 years, especially because our work is becoming more and more important with growing threats to global food production. Most of the food chain is in the hands of women. Empowering women to be in positions to make decisions on how to adapt is crucial to finding solutions to these challenges

Agreed, it’s wonderful to see so many women, such as Brindisi, entering the field. And it’s been educational and inspiring for me to collaborate with her — she’s going to make a meaningful impact wherever she lands, be it industry or academia.

If you want to get a behind-the-scenes peak at Brindisi’s work, follow her on Instagram at @larabrindisi.

Maintaining water culture systems

To keep a hydroponic system operating correctly, routine maintenance is required.

Fig. 1. Particulates in nutrient solution can end up clogging microtubing, reducing or eliminating the flow of solution to plants and causing unwanted and irreparable damage.
Photos courtesy of Christopher J. Currey

Hydroponic production systems can be very attractive. Their productivity and efficiency are a few of the qualities that draw people to them.

However, although their high-tech appearance and automated features give the impression these systems are low maintenance, that is certainly not the case. These systems are not crock pots where you can “set it and forget it;” rather, maintenance is required to keep them operating smoothly.

This article focuses on some of the routine maintenance required to keep water culture systems like nutrient-film technique (NFT) and deep-water culture (DWC) functioning their best year-round.

Focus on filters

Filters are commonly used to help keep particulates out of the nutrient solution. While loose organic substrates such as ground coconut coir and sphagnum peat moss used for hydroponic production are stabilized either chemically with a binder or physically with a spun-bound fabric or paper fiber wrapper, particles still come loose and get into the nutrient solution.

Even inorganic substrates including phenolic foam, which are stabilized by nature, can still sluff off particulates into the nutrient solution. Other organic debris, like dead root tissue and algae particles, can also build up and cause problems. Regular maintenance on your filter system will ensure consistent flow of nutrient solution throughout your system. This is especially important for in-line filters just before headers to microtubing. Failure to maintain filters not only slows or ultimately stops flows, but can also allow particulates to get into the system and clog lines (Fig. 1).

Clean those rafts and channels

Regardless of which system you are using, regular cleaning and maintenance of NFT channels and DWC rafts is essential. Each harvest is an opportunity to clean channels and rafts in good working condition, as well as sanitize them to reduce pathogens that are problematic to plant growth or human health. For NFT channels, inspect them for any damage that may be contributing to leaks. If the channels have end caps on them, make sure they are thoroughly attached; if not, set them aside to dry and reapply the adhesive you are using. While not the channel per se, taking time to inspect the microtubing and associate plumbing for NFT channels is useful. Make sure tubes are properly inserted into grommets, and that grommets are still on DWC rafts, inspect the polystyrene to ensure its integrity; cracks in the tray not only make them weaker and prone to breakage, but also serve as a place for algae to grow and establish.

In order to effectively sanitize rafts and channels, be sure to clean them first, then follow-up with a sanitizer. Regardless of which cleaners and sanitizers you are using, always make sure they are food grade and that you follow the manufacturers’ instructions. This will help ensure they are effective and safe. On a smaller scale, most raft and channel cleaning and sanitizing takes place by hand. Automation can help reduce the amount of labor it takes to clean and sanitize rafts (Fig. 2) and channels and, while it is most often used for large-scale operations, small-scale solutions are definitely possible (think: cleaning brush in an electric drill).

Reservoirs require periodic cleaning, too

Nutrient solution reservoirs also need to be kept as clean as possible to stop the spread of any unwanted plant or human pathogens and algae throughout production systems.

The best time to clean your nutrient reservoir is when systems are being flushed and nutrient solutions exchanged for fresh solution. Although nutrient solution exchanges are often done on a calendar basis, such as every three to four weeks, it is preferable to do it on an as-needed basis based on nutrient solution tests showing imbalances in nutrient concentrations or insufficient or excessive concentrations of nutrients. Taking this approach, you may find 100% exchanges are not occurring as often, reducing the opportunity to have an empty reservoir.

For algae management, treat the nutrient solution like a sump for fan-and-pad cooling. Keep it shaded to minimize sunlight reaching the tank to minimize algae growth; if possible, place it in the ground for maximize light blockage.

Biofilm is another issue hydroponic producers must contend with. Allowing biofilm to develop can increase the likelihood of plant and human pathogens building up in a system. Although periodic shock treatments to systems can help clean biofilm, a regular maintenance program can help keep it in check. There is already a good chance the techniques used to control biofilm are already being used to keep the health of hydroponic systems in check.

Ultraviolet (UV) sterilization is an effective practice and is also used for plant and human pathogens. Peracids, such as hydrogen peroxide products, are also effective for maintenance treatments. To maximize the effectiveness of these treatments, properly functioning filters help reduce particulates that can otherwise reduce their effectiveness in suppressing biofilms.

The practices outlined in this article are steps you can take each week to keep NFT and DWC systems operating smoothly and successfully. By paying attention to small details, you can avoid big problems in production.

Christopher (ccurrey@iastate.edu) is an associate professor in the Department of Horticulture at Iowa State University.

This guide contains articles from our sister publication Produce Grower. For more CEA-related coverage, visit ProduceGrower.com