Most cannabis stocks have been crushed during the stock market meltdown resulting from the coronavirus pandemic. But this major downturn presents opportunities to buy shares of the strongest players in the cannabis industry at discounted prices.

Which pot stocks are the best picks to buy in April? I'd put Innovative Industrial Properties (NYSE:IIPR), Square (NYSE:SQ), and Constellation Brands (NYSE:STZ) at the top of the list. Here's why these top cannabis stocks especially look attractive right now.

1. Innovative Industrial Properties

Perhaps no cannabis stock has taken a more undeserved hit during the coronavirus market crash than Innovative Industrial Properties. The cannabis-focused real estate investment trust (REIT) really shouldn't be affected much by the COVID-19 outbreak. 

IIP provides real estate capital to medical cannabis operators. The company's tenants are locked into long-term leases. Several key states have already declared medical cannabis as an essential business under stay-at-home regulations, moves that should improve the prospects for IIP's tenants to keep making their monthly lease payments. Super-low interest rates resulting in part from the pandemic could also help IIP in funding the purchases of additional properties.

I don't think that IIP will skip a beat in continuing its successful strategy of sale-leaseback deals with financially strong medical cannabis companies. This "rinse-and-repeat" approach enabled the company to grow its revenue by 269% in 2019 and boost its profits by more than fourfold. With additional expansion opportunities in the 15 states where it currently owns properties and more states with legal medical cannabis markets to target, IIP's remarkable momentum should continue.

Of course, I can't leave out the fact that Innovative Industrial Properties is the most attractive cannabis dividend stock on the market. Its dividend yield currently stands at close to 5.8%. IIP has boosted its dividend payout by 567% over the last three years. I expect more dividend increases will be on the way.  

2. Square

Square probably doesn't come to mind when you think about cannabis stocks. However, the company's decision last year to open up its payment platform to merchants selling CBD products gives Square a solid connection to the cannabis industry.

Unlike Innovative Industrial Properties, Square will be significantly affected by the COVID-19 crisis. Most of its customers are small and medium-sized businesses. With quarantines and social distancing measures in place throughout the U.S. and Canada, these customers' sales will plummet, causing Square's revenue to sink as well. It's not surprising that Square stock has fallen nearly 50% from its highs earlier this year.

But it's important to remember that the drastic measures taken to curb the spread of the novel coronavirus won't remain in place forever. Life for retailers should begin to return to some semblance of normality this summer. When that happens, Square will almost certainly rebound dramatically.

In the meantime, Square is in solid shape financially to weather the storm. It's profitable and had a cash stockpile topping $1 billion at the end of 2019. 

3. Constellation Brands

The cannabis connection for Constellation Brands has been in place since 2017. That's when the adult beverage giant first invested in leading Canadian cannabis producer Canopy Growth (NYSE:CGC). Constellation followed up the next year with an even bigger investment, upping its stake in Canopy to 38%.

So far, Canopy Growth has been a drag on Constellation's financial performance. But with former Constellation Brands CFO David Klein now at the helm as CEO of Canopy, the cannabis company should exercise a lot more fiscal discipline and establish a clear path to profitability.

Constellation's core business, though, continues to perform very well. The company's premium beers, led by Corona and Modelo, dominate the U.S. market. The COVID-19 outbreak will cause beer sales to be lower, especially with bars and restaurants shut down in much of the U.S. Again, though, this is only a temporary issue for Constellation. It's also being offset partially by increased sales to grocery stores and convenience stores.

I have no doubt whatsoever that Constellation's sales -- and its shares -- will bounce back soon. And I think that the Canadian cannabis derivatives market will serve as a nice tailwind for Canopy later this year and into 2021, which will help Constellation as well. Investors probably won't be able to buy Constellation at this big of a discount for too much longer.