Friday, 11 November 2016

The Watermelon Projects

Long-time blog readers will know that we are working on 2 watermelon breeding projects. Now that the season is over, it's time to assess how they are doing.

This was a terrific year for growing watermelon. It was a long, hot summer, in fact too dry throughout the middle although as the watermelons were beginning to be harvested it started to rain regularly, and I got to see how they stood up to the pressure to split in the face of a sudden influx of water. On the whole, they didn't do badly.

 In spite of the great conditions and the fact that we got excellent quantities of watermelon, I was a little disappointed with the results of this years grow-out, right from the beginning. It is not so bad that we need to give up, but there is going to be more work and more years going into these projects than I had hoped.


I'll start with the Golden-Rind project, as I guess I am now calling it. I am trying to create an improved version of Golden Midget, which turns yellow when ripe and is extremely early, but which also has enormous seeds, is very small, and the flavour tends to be a bit uneven.

Right from the start we had a hard time getting the seeds of our amazing lucky cross to germinate. Eventually, we had enough plants to fill the allotted bed but some of them went in quite late. The late ones were also late to produce fruit, even in such a marvellous year as this, which makes us reluctant to use them for future grow-outs. The late ones were also either green skinned or the size of golf balls. In spite of the earliness of Golden Midget, none of these were any earlier than our other, much larger, melons.

We did get 7 yellow skinned melons of edible size, ranging from 820 grams to 90 grams. (Yeah; 3 ounces to you. I'm taking a very generous view of what constitutes edible size.) The first 2 to ripen are shown in the above photo (GR001-0825 and GR002-0825). They were also the 2 largest yellow ripeners; the 820 gram one and a 600 gram one.


We still have to decide whether we will plant seeds only from the best couple next year or if we will plant from a larger selection. Right now I am leaning towards a larger selection including up to 3 of the ones that didn't turn yellow when ripe. We know they carry the yellow ripening gene on one side, so the odds that they will produce yellow ripening offspring are 50%, provided that they cross with one of the offspring of the yellow watermelons.

The above watermelon (GR007-0906) was interesting; it didn't turn yellow but it did have quite a large spot that did turn yellow. Partial expression of the yellow ripening gene? Or is it another different gene? I don't know, but still if I use a green-rinded watermelon in next years grow-out, this is a candidate. It was a decent size at 735 grams, had excellent texture and good flavour. (Flavour on the whole was weaker than I wanted by a fair bit, so that is a consideration.) On the down side, the seeds were a very nice small black, but more numerous than seemed reasonable to me.



The largest melon (GR010-0918, not shown) was 1.37 kilos, with nice light and dark green stripes, excellent texture, and good if a little mild flavour. Seeds were small, black and relatively few. Other than the fact that not even a spot turned yellow, the only negative point was that the colour was a little weak. I do think this one might make it into next years line-up.

Another candidate is GR004-0906 (above), which was a very decent 990 grams, also with a yellow spot when ripe. It was one of the best for good colour and flavour, but the texture was a little soft and the seeds, while black, were larger and more numerous than I wanted.

One interesting thing about this set of melons was that while the melons were extremely small upon the whole, so were the vines. You could have planted any three of these melons in a half-barrel planter and grown them quite nicely with a minimum of trellising. That may make them very good for many home gardeners.


The Orangeglo-Sweet Siberian project was also not as successful as we had hoped. We got lots of good melons, all grown from last years fabulous PJ09-0923, but none of them was as terrific as mom for flavour, and there were some definite issues with texture and storage qualities.

Interestingly, the vines of all the plants were surprisingly compact; normally they grow all over and we are picking them up and trying to send them back into the bed, or else we let them grow into the lawn and try to avoid mowing them. This year it was easy to keep them corralled. I do regard this as a good feature.

The above melon is PJ001-0822 and it was, in retrospect, one of the best. Very early, very sweet,  good texture, with small fairly dark seeds in reasonably low numbers. At 8 to 10 pounds it was a desirable size. The only negatives were its rather pale colouring and slightly too mild flavour. I guess I also thought the rind was a bit thick, but that's something I'm prepared to tolerate if everything else is good. This was the earliest and best of this phenotype, but it was a common type in the patch this year.


Here was a complete surprise. SU001-0829 was a melon that came up in last years mass cross bed, from a tiny handful seeds that survived the winter to sprout. This was the sturdiest and the only one we let grow. From the outside it looked a lot like a large Small Shining Light, but it turned out to be quite a bright yellow inside. It was also in the 8 to 10 pound range. The texture was very good, and it was probably the best tasting melon of the year! It lasted in the fridge for a long time.

We don't quite know what to do with it. We can't start growing out a 3rd set of watermelons; we haven't the room. Growing some elsewhere didn't pan out. We might fold it in with the Orangeglo-Sweet Siberian project; the colour is right, although it will almost certainly be carrying recessive red genes. That may not be a bad thing given that I thought too many of this years melons were too pale. Or we may be weeding out red watermelons for years to come.

Watermelon colour inheritance is very complex, with a number of possible genes that interact in different ways, sometimes within a single fruit. I do know that canary yellow is the most dominant colour; other yellows and oranges are less dominant. It seems fairly clear that this melon got its colour from the canary yellow gene, which surprises me. We were not growing any canary yellow fleshed melons, so if it is that dominant, how could it have been hidden? My guess is that it comes out of one of the orange fleshed melons, where the fact that it was a dominant source of colour was masked by the presence of another gene. 


In the above melon (PJ003-0901) you can see some of the problems we were having with texture this year - it's plainly loose and spongy. The colour is attractive and while the weight was only 4 pounds, that's really quite a desirable size. Alas, it was possibly overripe, and definitely a bit bland and quite mushy. Not a candidate for growing on.

This isn't it, but we did get one watermelon that had plainly crossed with something red fleshed. It was good and early ripening, but not good enough for me to contemplate keeping it in the herd. This seems to be a fairly typical rate of crossing between the 2 different projects, and as before I find it a tolerable level (like I have a choice).


PJ004-0902 (above) on the other hand had a super colour, and at just over 5.5 pounds a very nice size. The flavour was a little mild but good, and the texture was acceptable. Like its Orangeglo parent often does, it developed a fairly significant internal crack. The seeds were relatively few, small and black, and in spite of a slightly soft texture it held very well for several days in the fridge. I don't think the texture/cracking problems are sufficiently bad to disqualify it from growing on.


This one (PJ006-0906) was in many ways the best of the year. At 10.5 pounds, it was perhaps a shade on the large side - not the worst problem ever - but it had excellent colour, the best flavour of any from this project, very decent texture, and held up well in the fridge. It was big enough that I think it was in the fridge for close to 2 weeks before we ate it all, so it held up really very well. The only thing I didn't like about it was the seeds - they were pale and spotted like the Orangeglo parent's seeds, and fairly large and more abundant than I like to see.

It seems clear that for the Golden Rind project we will be selecting 6 to 10 melons to grow on. The Orangeglo-Sweet Siberian project is less clear. I don't know whether we will just grow on the one best melon (it will have been fertilized by other melons, after all) or if we should select a few others as well, and if so how many. At any rate, there's lots of time for the way to become clear by planting time.

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