Water availability and pepper heat

Sorry if this is the wrong forum for this or if it has already been posted, but I thought it might be relevant to this community:

http://news.sciencem...-wa.html?ref=hp

Excerpt: "They collected 330 C. chacoense plants from across a 300-kilometer-long area, which ranges from desert-like conditions in the northeast to very moist conditions in the southwest. The researchers found that only about 15% to 20% of the chili peppers produced in the dry conditions are hot, compared with 100% of the peppers from plants living in wet conditions."

Abstract of the actual paper (http://rspb.royalsocietypublishing.org/content/early/2011/12/15/rspb.2011.2091)

"Evolutionary biologists increasingly recognize that evolution can be constrained by trade-offs, yet our understanding of how and when such constraints are manifested and whether they restrict adaptive divergence in populations remains limited. Here, we show that spatial heterogeneity in moisture maintains a polymorphism for pungency (heat) among natural populations of wild chilies (Capsicum chacoense) because traits influencing water-use efficiency are functionally integrated with traits controlling pungency (the production of capsaicinoids). Pungent and non-pungent chilies occur along a cline in moisture that spans their native range in Bolivia, and the proportion of pungent plants in populations increases with greater moisture availability. In high moisture environments, pungency is beneficial because capsaicinoids protect the fruit from pathogenic fungi, and is not costly because pungent and non-pungent chilies grown in well-watered conditions produce equal numbers of seeds. In low moisture environments, pungency is less beneficial as the risk of fungal infection is lower, and carries a significant cost because, under drought stress, seed production in pungent chilies is reduced by 50 per cent relative to non-pungent plants grown in identical conditions. This large difference in seed production under water-stressed (WS) conditions explains the existence of populations dominated by non-pungent plants, and appears to result from a genetic correlation between pungency and stomatal density: non-pungent plants, segregating from intra-population crosses, exhibit significantly lower stomatal density (p = 0.003), thereby reducing gas exchange under WS conditions. These results demonstrate the importance of trait integration in constraining adaptive divergence among populations."

May be common knowledge, but it's nice to get some science out there.
 
That would line up with the capsaicin being produced as a kind of fungicide theory.
Were the moister areas also higher in elevation?
 
the island of trinidad is very moist...83 inches a year for rain...
 
Interesting but lets not forget that controlled water stress(keeping dry), heat stress, fertilizer stress etc will also make a pod hotter

I would be curious to know exactly how hot the hot desert plants are relative to the plants with adequate water. As you said, we know stressing can also produce a more pungent pepper through anecdotal experience. Presumably there is an optimum water to level to balance the two effects. Desert conditions are definitely above and beyond simply stressing a plant...
 
I think the trick is to only stress the plants once they are full of pods. I here of a lot of people trying to stress their plants before there are even pods on them :(
Plants do not enjoy stress, its a reaction to negative conditions. Although it likely makes pods hotter, I would imagine it would weaken the plant overall and you'd probably get a lot less production overall.
I think ideally plants like to go through a wet to dry cycle where not only water but oxygen is replenished on a constant bases
 
I think the trick is to only stress the plants once they are full of pods. I here of a lot of people trying to stress their plants before there are even pods on them :(
Plants do not enjoy stress, its a reaction to negative conditions. Although it likely makes pods hotter, I would imagine it would weaken the plant overall and you'd probably get a lot less production overall.
I think ideally plants like to go through a wet to dry cycle where not only water but oxygen is replenished on a constant bases

I am very curious about this, although i agree with it...If i forget to water a plant that is full of pods and it wilts etc etc etc....I notice dropped pods. Is there a fine line between stressed plants (pod drop) and stressed but still happy plants...
 
I am very curious about this, although i agree with it...If i forget to water a plant that is full of pods and it wilts etc etc etc....I notice dropped pods. Is there a fine line between stressed plants (pod drop) and stressed but still happy plants...
This season I prefer to avoid allowing my plants to wilt for the reason you've mentioned. I try to water the more developed plants right at the point when the water is needed.

There are some prolific plants here that power on producing more pods than I need despite frequent wilting before watering such as my Bishop's Hat and Aji Omnicolor plants . Other plants though have dropped pods after wilting.

The water stress suffered by the Bishop's Hat plant last season resulted in it producing very hot pods that were hotter than expected from this variety. The pods that developed during less hot periods when the plant wilted less were considerably milder.

I have a Jalapeño variety that produces heat-less pods when the plant is watered every day. This one was a disappointment given the brand of "Fire Eater" and the words very hot on the tag.

Hence in regards to the study my experience with domesticated varieties has been the reverse of their findings.
 
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